Last changes

Exercise 1-2/questions.md

@@ -2,7 +2,7 @@
 
 ## 1. Why does inline style CSS override rules defined in style elements and external stylesheets?
 
-  inline style CSS overrides external stylesheets because it's the most specific ruleset. Rules from external stylesheets might match the object, but if you know that this specific element should be styled differently, it could be written explicitly in the tag options of the element. However, best practise would be to use an ID.
+  inline style CSS overrides external stylesheets because it's the most specific ruleset. Rules from external stylesheets might match the object, but if you know that this specific element should be styled differently, it could be written explicitly in the tag options of the element. However, in this case it would be best practise to use an ID and specify the rules in a stylesheet.
 
 ## 2. Give a brief example of when to use ID ( #id ) and when to use classes ( .class ) in CSS.
  
@@ -12,7 +12,7 @@
 
   RGBA is an acronym meaning "Red, Green, Blue, Alpha" where the three first represent subpixel brightness values and the fourth represents opacity. With the RGB colors, you can express most colors that anyone can think of on the top of their head. Usually, we express them with a bitdepth of 8, meaning you can specify each individual color value to a range of 2^8 values -> between 0 and 255. With the alpha channel added, we can also specify how transparent the color should be. This is especially useful for things like non-square icons, watermarks and in web development - see-through floating windows. An example of a color that could be expressed with RGBA would be a 50% seethrough yellow, RGB(255,255,0, 127), or with alternative hexadecimal syntax -> #FFFF007f.
   
-  Note that the actual amount of colors you can express with RGBA depends on several other factors like your monitor, the colorspace, the brightness in the room you're sitting
+  Note that the actual amount of colors you can express with RGBA depends on several other factors like your monitor, the colorspace, the brightness in the room you're sitting.
   
   ![Diagram showing hue along the x axis and opacity along the y axis](https://upload.wikimedia.org/wikipedia/commons/0/0b/RGBA_comp.png)
 
@@ -23,7 +23,27 @@
 ## 5. What CSS selector matches all the p elements inside the article element in the following HTML?
 
   ```HTML
+  <p>This should not match.</p>
+  <article>
+    <h2>This should not match</h2>
+    <p>This should match.</p>
+    <p>This should also match.</p>
+    <p>Do not forget about this one!</p>
+  </article>
+  ```
+
+  Here, we have two options. You could either do
+
+  ```CSS
     article p {}
   ```
  
-  This specifies all `<p>` elements inside the `<article>`, in contrast to `article > p {}` which would only specify `<p>` elements directly beneath the `<article>`.
+  which specifies all `<p>` elements inside the `<article>`.
+  
+  The other option would be 
+  
+  ```CSS
+    article > p {}
+  ```
+  
+  which would only specify `<p>` elements directly beneath the `<article>`. But since `<article>` has no `<p>` subchildren, both will work.

Exercise 3/a.txt

@@ -0,0 +1,11 @@
+1. The difference between `position: absolute;` and `position: fixed;` is that the absolute element is fixed onto the page itself, but the fixed element is fixed onto the "screen" or web browser so to say. If you scroll down, the fixed element won't move, but the absolute value will follow the page as any other unstyled element.
+
+2. 
+
+```CSS
+  element > anotherElement:nth-of-type(3n) {
+    ...
+  }
+```
+
+[//]: # vim: set syntax=markdown:

Exercise 3/css/style.css

@@ -0,0 +1,34 @@
+html, body{
+  margin: 0;
+  padding: 0;
+  height: 100%;
+}
+
+/* Part 3 */
+
+.wrapper {
+  padding-bottom: 60px;
+}
+
+.wrapper footer {
+  position: fixed;
+  bottom: 0;
+  padding: 20px 40px;
+  font-size: 20px;
+  color: white;
+  background-color: #404040C0;
+  margin-block-end: 0;
+  width: 100%;
+  text-align: center;
+}
+
+
+/* Part 4 */
+
+li {
+  list-style-type: square;
+}
+
+ul > ul > li:last-child {
+  font-weight: 900;
+}

Exercise 3/list.html

@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>A list apart</title>
+    <link rel="stylesheet" href="css/style.css">
+  </head>
+  <body>
+
+    <div class="wrapper">
+      <h1>This is a list</h1>
+
+      <ul>
+        <li>HTML5</li>
+        <li>CSS</li>
+        <ul>
+          <li>LESS</li>
+          <li>Sass</li>
+          <li>SCSS</li>
+        </ul>
+        <li>JavaScript</li>
+        <ul>
+          <li>React</li>
+          <li>Node</li>
+          <li>Jquery</li>
+          <li>AngularJS</li>
+          <li>Backbone</li>
+          <li>Ember</li>
+          <li>Babel</li>
+        </ul>
+      </ul>
+      <footer>Here's some footer text</footer>
+    </div>
+
+  </body>
+</html>

Exercise 3/position.html

@@ -0,0 +1,133 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>IT2805</title>
+
+  <style type="text/css">
+
+    html, body{
+      margin: 0;
+      padding: 0;
+      height: 100%;
+    }
+    /* Part 1 */
+
+    .header{
+      font-family: sans-serif;
+      padding-top: 30px;
+      margin-bottom: 40px;
+    }
+
+    .box{
+      border-width: 2px;
+      border-color: #0060A3;
+      border-style: solid;
+      height: 400px;
+
+      margin: 0 25%;
+    }
+
+    .one{
+      width: 100px;
+      height: 100px;
+      border-width: 2px;
+      border-color: #FAA21B;
+      border-style: solid;
+
+      margin-top: 25px;
+      margin-left: 25px;
+    }
+
+    .two{
+      width: 100px;
+      height: 100px;
+      border-width: 2px;
+      border-color: #FAA21B;
+      border-style: solid;
+      background-color: #fff;
+
+      margin-left: 25px;
+      position: relative;
+      top: 145px;
+      
+    }
+
+    .three{
+      width: 100px;
+      height: 100px;
+      border-width: 2px;
+      border-color: #FAA21B;
+      border-style: solid;
+      background-color: #fff;
+
+      margin-left: auto;
+      position: relative;
+      left: 50px;
+      bottom: 150px;
+
+    }
+
+    .five{
+      bottom: 10px;
+      font-size: 35px;
+      font-family: sans-serif;
+
+      text-align: right;
+      margin-right: 25px;
+    }
+
+    .four{
+      width: 50px;
+      height: 50px;
+      border-width: 2px;
+      border-color: #FAA21B;
+      border-style: solid;
+      
+      margin: 25px auto;
+    }
+
+    /* Part 2 */
+
+    a {
+      color:blue;
+    }
+
+    a:hover {
+      color: cyan;
+    }
+
+    a::selection {
+      background-color: orange;
+    }
+
+    a:visited {
+      color: purple;
+    }
+    
+    a:visited:hover {
+      color: green;
+    }
+
+  </style>
+</head>
+<body>
+
+    <div class="header">
+      <h1>Assignment 3: position</h1>
+    </div>
+
+    <div class="box">
+      <div class="one"></div>
+      <div class="two"></div>
+      <div class="three">
+        <div class="four"></div>
+      </div>
+      <div class="five">
+        <a href="https://developer.mozilla.org/en-US/docs/Web/CSS">CSS is awesome</a>
+      </div>
+    </div>
+
+
+
+</body>
+</html>

Exercise 4/css/style.css

@@ -0,0 +1,57 @@
+  * {
+    margin: 0;
+    padding: 0;
+  }
+
+  body {
+    background: white;
+    font-family: arial, sans-serif;
+  }
+
+  #screen {
+    position: relative;
+  }
+
+  video {
+    height: auto;
+    width: 100%;
+  }
+
+  #mobile-image {
+    height: auto;
+    width: 100%;
+    display: none;
+  }
+    
+  #title {
+    position: absolute;
+    top: 50%;
+    left: 50%;
+    transform: translate(-50%, -50%);
+  }
+
+  #title > img {
+    width: 100%;
+  }
+
+  article {
+    width: 80%; /* 100% - 10% left - 10% right = 80% */
+    margin: 20px auto;
+  }
+
+  p {
+    color: black;
+    font-size: 16px;
+    line-height: 1.5;
+  }
+
+
+@media screen and (max-width: 940px) {
+  video {
+    display: none;
+  }
+  #mobile-image {
+    display: block;
+  }
+}
+

Exercise 4/index.html

@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<html>
+  <head>
+      <title>HTML5 Video and CSS</title>
+      <meta charset="utf-8">
+      <link rel="stylesheet" href="css/style.css">
+  </head>
+  <body>
+    <div id="screen">
+
+      <video autoplay muted loop poster="img/hovedbygget.png">
+        <source src="videos/hovedbygget.mp4" type="video/mp4">
+        <source src="videos/hovedbygget.ogv" type="video/ogv">
+        <source src="videos/hovedbygget.webm" type="video/webm">
+      </video>
+      <img id="mobile-image" src="img/hovedbygget.png" alt="Hovedbygget på ntnu">
+
+      <div id="title">
+        <img src="img/ntnu.png" alt="NTNU" />
+      </div>
+
+    </div>
+
+    <article class="content">
+      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
+    </article>
+
+  </body>
+</html>

Exercise 4/questions.txt

@@ -0,0 +1,25 @@
+# Questions
+
+1. Mobile phones usually ignore the autoplay tag in order to save cellular data.
+
+2. The css snippet 
+  ```CSS
+    @media only screen
+      and (min-device-width : 768px)
+      and (max-device-width : 1024px) {
+        #logo {
+          display: none;
+        }
+    }
+  ```
+  will make no difference for a device with `320 x 568` resolution because the device' height, `568px`, is not between `768` and `1024`
+
+3. There is several advantages of using a responsive website. Some of them are:
+
+  * A collected codebase: There is not as much work to do as if you were to make two different sites.
+
+  * The user is guaranteed the same info: The HTML will stay the same no matter how the CSS is written, and there will be less occurences of the mobile website not having the same services/options/information as the desktop website or vice versa.
+
+  * Easier networking: No need for any special redirection proxys or desktop/mobile specific load balancer. You can just serve the website as is.
+
+[//]: # vim: set syntax=markdown:

Exercise 5/index.html

@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+  <meta charset="utf-8">
+  <title>IT2805 assignment 5: JavaScript introduction</title>
+
+  <style>
+    .box {
+      /* Sets the size and position of each box */
+      width: 200px;
+      height: 200px;
+      background-color: #185D8B;
+      margin: 10px;
+
+      /* Sets the font within each box*/
+      color: #fff;
+      font-family: Helvetica, Arial, sans-serif;
+      text-align: center;
+      line-height: 200px;
+      font-size: 100px;
+    }
+
+    .buttons {
+      width: 200px;
+      margin: 10px;
+      text-align: center;
+    }
+  </style>
+  <script src="./script.js" defer></script>
+  <!-- 
+    I am including it here because it makes sense for
+    everything that's not content to be placed in the <head>.
+    I do know however that this usually causes problems with
+    accessing the DOM, because the script runs before the page
+    is loaded. The defer option will take care of this.
+  -->
+
+
+</head>
+
+<body>
+
+  <h1 id='title'></h1>
+
+  <h2>Part 5</h2>
+  <div class='buttons'>
+    <button id='displayButton'>Display: none </button>
+    <button id='visibilityButton'>Visibility: hidden</button>
+    <button id='resetButton'>Reset</button>
+  </div>
+  <div class='box' id='magic'> 1 </div>
+  <div class='box'> 2 </div>
+
+  <h2>Part 6</h2>
+  <ul id='tech'>
+  </ul>
+
+</body>
+
+</html>

Exercise 5/script.js

@@ -0,0 +1,91 @@
+/* -------------------------------------------------------------------------- */
+/*                                   Part 2                                   */
+/* -------------------------------------------------------------------------- */
+
+console.log('PART 2')
+
+/* Log i from 1 until i is no longer less than or equal to 20 */
+for (i=1; i<=20; i++) {
+  console.log(i);
+}
+
+/* -------------------------------------------------------------------------- */
+/*                                   Part 3                                   */
+/* -------------------------------------------------------------------------- */
+
+console.log('PART 3')
+
+const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
+
+/* A function that returns eple and/or kake if it's divisible by 3 or 5, but defaults
+*  to n if it's not (an empty string combined with || will return the latter element)
+*/
+const eplekakeCheck = (n) => (n % 3 ? '' : 'eple') + (n % 5 ? '' : 'kake') || n;
+
+/* Print the output of eplekakeCheck for each element in numbers */
+for (i of numbers) {
+  console.log(eplekakeCheck(i));
+}
+
+/* -------------------------------------------------------------------------- */
+/*                                   Part 4                                   */
+/* -------------------------------------------------------------------------- */
+
+/* Store the DOM node as a variable and change its innerText */
+const title = document.getElementById("title");
+title.innerText = 'Hello JavaScript';
+
+/* -------------------------------------------------------------------------- */
+/*                                   Part 5                                   */
+/* -------------------------------------------------------------------------- */
+
+const magicBox = document.getElementById('magic');
+
+function changeDisplay () {
+  magicBox.style.display = 'none'
+}
+
+function changeVisibility () {
+  magicBox.style.display = 'block'
+  magicBox.style.visibility = 'hidden'  
+}
+
+function reset () {
+  magicBox.style.display = 'block'
+  magicBox.style.visibility = 'visible'
+}
+
+/* Connect each button to their respective function */
+document.getElementById('displayButton').addEventListener('click', changeDisplay);
+document.getElementById('visibilityButton').addEventListener('click', changeVisibility);
+document.getElementById('resetButton').addEventListener('click', reset);
+
+/* -------------------------------------------------------------------------- */
+/*                                   Part 6                                   */
+/* -------------------------------------------------------------------------- */
+
+const technologies = [
+    'HTML5',
+    'CSS3',
+    'JavaScript',
+    'Python',
+    'Java',
+    'AJAX',
+    'JSON',
+    'React',
+    'Angular',
+    'Bootstrap',
+    'Node.js'
+];
+
+const technologyList = document.getElementById("tech");
+
+/* 
+  for each technology, create an HTML element, add the technology as innertext and append
+  the element as a child of the list
+*/
+for (technology of technologies) {
+  const listElement = document.createElement('li');
+  listElement.innerText = technology;
+  technologyList.appendChild(listElement);
+}

Exercise 6/index.html

@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+  <title>Tax form</title>
+  <meta charset="utf-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <link rel="stylesheet" href="./style.css">
+  <script src="./script.js" defer></script>
+</head>
+
+<body> 
+
+
+  <header>
+    <h1>Hero tax</h1>
+  </header>
+
+  <form action="http://folk.ntnu.no/michaedm/norwegian-tax-administration/receive.php" method="post">
+    <label for="nameInput">Real name</label>
+    <input type="text" name="name" id="nameInput" pattern="[A-Za-z]+" title="Please use only alphanumeric characters" autofocus required>
+
+    <!-- Another option for genders would've been radio buttons -->
+
+    <label for="genderInput">Gender</label>
+    <select name="gender" id="genderInput" required>
+      <option value="">None</option>
+      <option value="male">Male</option>
+      <option value="female">Female</option>
+    </select>
+
+    <label for="emailInput">E-mail</label>
+    <input type="email" name="email" id="emailInput" required>
+
+    <!-- This might not return the value in the DD.MM.YYYY format, but it's usually considered to be the safest and most correct method for date inputs. Also, even though the html validator doesn't like it, the regexp is only used as a fallback field if the browser has no native date picker (see https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/date#Handling_browser_support). If you need conversion for something like a database, this would usually be done in javascript -->
+
+    <label for="birthdayInput">Birthdate</label>
+    <input type="date" name="birthday" id="birthdayInput" max="1987-12-31" pattern="\d{2}\.\d{2}\.\d{4}" required>
+
+    <label for="heroInput">Hero name</label>
+    <input type="text" name="hero" id="heroInput" required>
+
+    <div class="inline">
+      <label for="wearsSpandexInput">Do you wear spandex?</label>
+      <input type="checkbox" name="spandex" id="wearsSpandexInput" required>
+    </div>
+
+    <div id="sliders">
+
+      <!-- I made these inputs as sliders because I felt it made more sense considering the "floatish" nature of these properties. If we had been allowed to use javascript for this task, I probably also would've added some kind of a number that would show the slider value. If it's really important that these values could be specified as an exact value, you would only need to change the type from "range" to "number" (and maybe add a required-attribute). Min, max and step will work in the same way. -->
+
+      <label for="strengthInput">Strength</label>
+      <input type="range" name="strength" id="strengthInput" min="1" max="10" step="1">
+      <label for="speedInput">Speed</label>
+      <input type="range" name="speed" id="speedInput" min="1" max="10" step="1">
+
+      <label for="intelligenceInput">Intelligence</label>
+      <input type="range" name="intelligence" id="intelligenceInput" min="1" max="10" step="1">
+    </div>
+
+    <div id="taxFields">
+      <label for="incomeInput">Income</label>
+      <input type="number" name="income" id="incomeInput" min="0" step="1" required>
+
+      <label for="wealthInput">Wealth</label>
+      <input type="number" name="wealth" id="wealthInput" min="0" step="1" required>
+
+      <label for="taxInput">Tax</label>
+      <input type="number" name="tax" id="taxInput" readonly>
+    </div>
+
+    <input type="submit" value="Submit" id="submitButton">
+  </form>
+</body>
+
+</html>

Exercise 6/questions.txt

@@ -0,0 +1,23 @@
+# Questions
+
+1. Why does the expression `0.1 + 0.2 === 0.3` evaluate to `false` in javascript?
+
+Because of how most programming languages represent fractions, not all numbers can be represented correctly. Just like how we can't represent 1/3 in our base 10 number system, neither 0.1 nor 0.2 can't be represented without recurring digits, and therefore we end up with an approximation. `0.1 + 0.2` is a pretty common example of this, and it resolves to `0.30000000000000004`
+
+2. What does the `method` attribute on a `form` element decide?
+
+The `method` of on a `form` decides what kind of HTTP request to send on submission. `POST` and `ADD` are the most normal ones to use for this. You might use `GET` if the data isn't sensitive.
+
+3. Explain why the form fields appear in the URL when the `method` on `form` element is changed to `GET`?
+
+There are several types of HTTP requests. Some of them are quite similar but named differently for semantic purposes. `GET` and `POST` however, are quite different. `POST` is a generic request used for sending data to a server. Therefore, the packets contain data fields, and it can even be encrypted. `GET` however is only supposed to be used to fetch information from the server. `GET` requests have no data fields. If you want to include any modifiers or data in the request, it has to go in the URL of the request (with a few exceptions for metadata such as some kinds of system information, cookies, authentication certificates etc.)
+
+4. Why is it considered bad practise to only validate form input with HTML5 and/or Javascript?
+
+You can't run all kinds of validation in HTML. There are only basic, but often used options for HTML validation. Javascript however can do a lot more advanced validation, but using this to reimplement everything that the browser already does for you is bad practise. You would essentially be reinventing the wheel. It also means you'd have to take care of things like giving the user feedback on what's wrong. In the end, you would also want backend validation on a real project so no one can just bypass the html and javascript validation with sending an http request directly containing bad or even malicious data.
+
+5. When is it appropriate to use `textarea` over `input`?
+
+`textarea` is used whenever you have a long text, such as a tweet, a paragraph or really just anything longer than a few words. If the user is going to write more than one sentence, textarea is usually easier to work with than `input`. While it is still possible to force `input` to act as some kind of textfield, it's bad practise to do so. The text type `input` tag is really only meant for short entries such as names, usernames, food preferences etc.
+
+[//]: # vim: set syntax=markdown:

Exercise 6/script.js

@@ -0,0 +1,15 @@
+
+const [incomeInput, wealthInput, taxInput] = ["incomeInput", 'wealthInput', 'taxInput']
+  .map(id => document.getElementById(id));
+
+const tax = (income, wealth) => (0.35 * income) + (0.25 * wealth);
+
+const updateTax = () => {
+  const [income, wealth] = [incomeInput.value, wealthInput.value]
+    .map(value => parseInt(value))
+    .map(value => isNaN(value) ? 0 : value);
+  taxInput.value = tax(income, wealth);
+}
+
+incomeInput.addEventListener('input', updateTax);
+wealthInput.addEventListener('input', updateTax);

Exercise 6/style.css

@@ -0,0 +1,58 @@
+body {
+  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
+  background-color: grey;
+}
+
+h1 {
+  text-align: center;
+  color: #2b68d8;
+  padding: 10px;
+  border-radius: 20px;
+  background-color: #DFDFDF;
+  margin: 30px 10%;
+}
+
+form {
+  margin: 0 10%;
+  background-color: #DFDFDF;
+  padding: 50px;
+  border-radius: 20px;
+}
+
+input, select {
+  display: block;
+  margin-bottom: 20px;
+}
+
+input[type=text], input[type=number], input[type=email], input[type=date], select {
+  border-radius: 5px;
+}
+
+input[type=submit] {
+  font-size: large;
+  border-radius: 5px;
+  color: #2b68d8;
+  background-color: #DDDDDD;
+}
+
+input[type=submit]:hover {
+  background-color: #FFFFFF;
+}
+
+
+#sliders input, #taxFields input {
+  display: inline;
+  margin-right: 20px;
+}
+
+#sliders {
+  margin: 20px 0;
+}
+
+#taxFields {
+  margin: 20px 0;
+}
+
+.inline * {
+  display: inline;
+}

Exercise 6/table.txt

@@ -0,0 +1,7 @@
+The PDF didn't want to cooperate so here you have the table for part 6. 
+
+| Real name   | Gender | E-Mail                     | Birthyear | Hero name | Spandex | Strength | Speed | Intelligence | Wealth     | Income    | Tax
+|-------------|--------|----------------------------|-----------|-----------|---------|----------|-------|--------------|----------- |-----------|-----
+| Nick Nedd   | Male   | nick@tick.com              | 1976      | The Tick  | Yes     | 9        | 7     | 5            | 0          | 90 287    | 29 794
+| Bruce Wayne | Male   | bruce@wayneenterprises.com | 1974      | Batman    | No      | 7        | 4     | 9            | 50 144 501 | 3 343 891 | 11 132 384
+| Selina Kyle | Female | selina@whiskas.com         | 1977      | Catwoman  | Yes     | 6        | 6     | 9            | 2 987 323  | 0         | 597 464

Exercise 6/taxes.xml

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<people>
+  <person>
+    <name>Nick Nedd</name>
+    <gender>Male</gender>
+    <email>nick@tick.com</email>
+    <birthyear>1976</birthyear>
+    <hero>The Tick</hero>
+    <spandex>True</spandex>
+    <strength>9</strength>
+    <speed>7</speed>
+    <intelligence>5</intelligence>
+    <wealth>0</wealth>
+    <income>90287</income>
+    <tax>29794</tax>
+  </person>
+  <person>
+    <name>Bruce Wayne</name>
+    <gender>Male</gender>
+    <email>bruce@wayneenterprises.com</email>
+    <birthyear>1974</birthyear>
+    <hero>Batman</hero>
+    <spandex>False</spandex>
+    <strength>7</strength>
+    <speed>4</speed>
+    <intelligence>9</intelligence>
+    <wealth>50144501</wealth>
+    <income>3343891</income>
+    <tax>11132384</tax>
+  </person>
+  <person>
+    <name>Selina Kyle</name>
+    <gender>Female</gender>
+    <email>selina@whiskas.com</email>
+    <birthdate>1977</birthdate>
+    <hero>Catwoman</hero>
+    <spandex>True</spandex>
+    <strength>6</strength>
+    <speed>6</speed>
+    <intelligence>9</intelligence>
+    <wealth>2987323</wealth>
+    <income>0</income>
+    <tax>597464</tax>
+  </person>
+<people>

Exercise 7/todo.css

@@ -0,0 +1,71 @@
+body {
+  background-color: #272822;
+  color: #F8F8F8;
+  margin: 5% 20%;
+}
+
+#title {
+  text-align: center;
+  color: #A6E22E;
+  font-size: 4em;
+}
+
+#todoField {
+  display: block;
+  padding: 1em;
+  margin: 0 auto;
+  color: #F8F8F8;
+  background-color: #494b41;
+  font-size: 2em;
+  resize: none;
+}
+
+#todoButton {
+  display: block;
+  padding: 1em;
+  margin: 1em auto;
+  color: black;
+  background-color: #FD971F;
+  font-size: 1.5em;
+  filter: drop-shadow(0.5em 0.5em 2px #191a16);
+  cursor: pointer;
+}
+
+#todoSummary {
+  font-size: 3em;
+  text-align: center;
+}
+
+#todoList {
+  list-style-type: none;
+}
+
+input[type=checkbox] {
+  width: 2em;
+  height: 2em;
+  margin-right: 2em;
+  vertical-align: middle;
+  cursor: pointer;
+}
+
+#todoList>li>span {
+  display: inline-block;
+  font-size: 3em;
+}
+
+#todoList>li {
+  margin-bottom: 1.5em;
+}
+
+/* Monokai rainbow list :DDD */
+#todoList>li:nth-child(7n+1) {color: #F92672;}
+#todoList>li:nth-child(7n+2) {color: #FD971F;}
+#todoList>li:nth-child(7n+3) {color: #E69F66;}
+#todoList>li:nth-child(7n+4) {color: #E6DB74;}
+#todoList>li:nth-child(7n+5) {color: #A6E22E;}
+#todoList>li:nth-child(7n+6) {color: #66D9EF;}
+#todoList>li:nth-child(7n)   {color: #AE81FF;}
+
+.strikethrough {
+  text-decoration: line-through;
+}

Exercise 7/todo.html

@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <title>Todo</title>
+  <link rel="stylesheet" href="./todo.css">
+  <script src="./todo.js" defer></script>
+</head>
+<body>
+
+  <h1 id="title">Todo-list</h1>
+  <textarea id="todoField" cols="60" rows="2" autofocus ></textarea>
+  <button id="todoButton">Add task (Enter)</button>
+  <div id="todoSummary"></div>
+  <ul id="todoList"></ul>
+  
+</body>
+</html>

Exercise 7/todo.js

@@ -0,0 +1,91 @@
+const todoField = document.getElementById("todoField");
+const todoButton = document.getElementById("todoButton");
+const todoSummary = document.getElementById("todoSummary");
+const todoList = document.getElementById("todoList");
+
+/**
+ * A task for the todolist
+ * @typedef {Object} Task
+ * @property {number} createdAt - Timestamp of the time that the task was created.
+ * @property {string} description - Description of the task.
+ * @property {boolean} isCompleted - Whether or not the task is completed.
+ */
+
+const tasks =  [];
+
+/**
+ * Add task to both tasks and DOM
+ */
+addTask = () => {
+  tasks.push({
+    createdAt: Date.now(),
+    description: todoField.value,
+    isCompleted: false
+  });
+
+  const taskElement = createTaskElement(tasks[tasks.length - 1]);
+  todoList.prepend(taskElement);
+  
+  todoField.value = '';
+  todoField.focus();
+
+  updateSummary();
+};
+
+/**
+ * Generate HTML element for a task
+ * @param {Task} task - The task to be converted into an html element
+ * @return {HTMLLIElement} The <li> element
+ */
+createTaskElement = (task) => {
+  const listItem = document.createElement('li');
+
+  const checkbox = document.createElement('input');
+  checkbox.type = 'checkbox';
+  checkbox.name = tasks.length - 1
+  checkbox.addEventListener('change', updateCheckbox);
+  listItem.appendChild(checkbox);
+
+  const description = document.createElement('span');
+  description.innerText = task.description;
+  listItem.appendChild(description);
+  
+  return listItem;
+}
+
+/**
+ * Function to react to change on a checkbox
+ * @param {Event} event - the event raised by the eventlistener
+ */
+updateCheckbox = (event) => {
+  const index = tasks.length - event.target.name - 1;
+  tasks[index].isCompleted = event.target.checked;
+
+  const descriptionSpanClasses = todoList
+    .children[index]
+    .getElementsByTagName('span')[0]
+    .classList
+
+  if (event.target.checked) descriptionSpanClasses.add('strikethrough');
+  else descriptionSpanClasses.remove('strikethrough');
+
+  updateSummary();
+}
+
+/**
+ * Update the summary span with new task values
+ */
+updateSummary = () => {
+  const tasksCompleted = tasks.filter(task => task.isCompleted).length;
+  todoSummary.innerText = `${tasksCompleted}/${tasks.length} completed.`;
+}
+
+/**
+ * Handle the global keypresses and react on certain ones.
+ */
+handleKeys = (event) => {
+  if (event.which === 13 && document.activeElement === todoField) addTask();
+}
+
+todoButton.addEventListener('click', addTask);
+document.addEventListener('keyup', handleKeys);

Exercise 8/bar-chart-with-bars.html

@@ -0,0 +1,184 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Tax forms: Bar chart with lines</title>
+    <meta charset="UTF-8">
+    <script src="taxForms.js"></script>
+  </head>
+  <body>
+
+    <canvas id="chart" width="700" height="550"></canvas>
+
+    <script>
+      const canvas = document.getElementById('chart');
+      const context = canvas.getContext('2d');
+
+      /* Draw a line from (fromX, fromY) to (toX, toY) */
+      function drawLine(fromX, fromY, toX, toY) {
+        context.beginPath();
+        context.moveTo(toX, toY);
+        context.lineTo(fromX, fromY);
+        context.stroke();
+      }
+
+      /* Draw a text (string) on (x, y) */
+      function drawText(text, x, y) {
+        context.fillStyle = 'black';
+        context.fillText(text, x, y);
+      }
+
+      /* Draw a text and with a line to its right */
+      function drawLineWithText(text, fromX, fromY, toX, toY) {
+        drawText(text, fromX - 50, fromY + 10);
+        drawLine(fromX, fromY, toX, toY);
+      }
+
+      /* Insert your code here. */
+
+      /**
+       * Draw lines on the y axis of the canvas
+       * 
+       * @param {number} n - Number of lines to draw
+       * @param {number} step - Number to add to y axis
+       */
+      const drawNLines = (n, step) => {
+        const yOffset = i => canvas.height * (n - i + 1 ) / (n+1);
+        for (let i = 1; i <= n; i++)
+          drawLineWithText(step * i, 50, yOffset(i), canvas.width - 100, yOffset(i));
+      }
+
+      /**
+       * Draws a rectangle onto the canvas
+       * 
+       * @param {number} x - x value of the upper left corner of the rectangle
+       * @param {number} y - y value of the upper left corner of the rectangle
+       * @param {number} width - Width of the rectangle
+       * @param {number} height - Height of the rectangle (DOWNWARDS)
+       * @param {string} color - Color of the rectangle
+       */
+      const drawRectangle = (x, y, width, height, color='red') => {
+        context.fillStyle = color;
+        context.fillRect(x, y, width, height);
+      }
+
+      /**
+       * Cycle a list of colors
+       * 
+       * @generator
+       * 
+       * @param {string[]} colors - List of colors to cycle
+       * @yields {string} A color
+       */
+      function* colorCycler(colors) {
+        while (true) 
+          for (color of colors) 
+            yield color;
+      }
+
+      /**
+       * Draw a legend on the canvas
+       * 
+       * @param {string[]} properties - An array of labels
+       * @param {[string[]} colorList - An array of colors to cycle when making labels
+       */
+      const drawLabels = (properties, colorList) => {
+        const colors = colorCycler(colorList);
+
+        const drawLabel = (text, color, y) => {
+          drawText(text, canvas.width - 45, y + 15);
+          drawRectangle(canvas.width - 90, y, 40, 20, color);
+        }
+
+        const yOffset = i => canvas.height / 12 + 30 * i;
+        for (i in properties)
+          drawLabel(properties[i], colors.next().value, yOffset(i));
+      }
+
+      /**
+       * Draw a subset of bars on the canvas
+       * 
+       * param {{
+       *   x: number,
+       *   width: number,
+       *   adjustY: {val: number}=>number,
+       *   object: Object.<string, number>,
+       *   sep: number,
+       *   colorList: string[] 
+       * }} config - 
+       *   x: x value of where to start drawing bars
+       *   width: Width of all the bars to draw collected
+       *   adjustY: A function to adjust the y value of each bar to the upper left corner
+       *   object: The object containing the values to draw
+       *   sep: The amount of pixels between each bar
+       *   colorList: A list of colors to cycle when creating bars
+       */
+      const drawBars = ({x, width, adjustY, object, sep, colorList}) => {
+        const colors = colorCycler(colorList);
+        const values = Object.values(object);
+
+        const drawBar = (value, x) => 
+          drawRectangle(
+            x,
+            adjustY(value),
+            width / (values.length) - sep,
+            canvas.height - adjustY(value), 
+            colors.next().value
+          );
+        
+
+        const xOffset = i => x + i * (sep + width / (values.length));
+        for (let i=0; i<values.length; i++) 
+          drawBar(values[i], xOffset(i));
+
+        colors.return();
+      }
+
+      /**
+       * Draw an array of objects as a diagram onto the canvas
+       * 
+       * @param {Array.<Object.<string, number>>} data - An array of objects with graphable properties
+       * @param {string[]} colorList - An array of colors to cycle when drawing bars
+       * @param {{val: number}=>number} adjustY - A function to adjust the y value of
+       *   each bar to the upper left corner
+       */
+      const drawColumnSet = (data, colorList, adjustY) => {
+        const lineWidth = canvas.width - 150;
+        const columnSetWidth = lineWidth / (2 * data.length + 1) - data.length + 1;
+        const initialXOffset = 50 + columnSetWidth;
+        const xOffset = 2*columnSetWidth;
+
+        for (i in data)
+          drawBars({
+            x: initialXOffset + i*xOffset,
+            width: columnSetWidth,
+            adjustY: adjustY,
+            object: data[i],
+            sep: 5, 
+            colorList: colorList
+          });
+      }
+
+      /**
+       * Draw a bar chart diagram
+       * 
+       * @param {Array.<Object.<string, number>>} data - An array of objects with graphable properties
+       * @param {number} range - The upper range of the graph (the top line)
+       * @param {number} step - The number to increase by for every unit on the axis
+       */
+      const drawDiagram = (data, range, step) => {
+        drawNLines(range/step, step);
+
+        const colorList = ['red', 'blue'];
+        drawLabels(Object.getOwnPropertyNames(data[0]), colorList);
+
+        const adjustY = val => canvas.height * ( 1 - val / (range + step));
+        drawColumnSet(data, colorList, adjustY);
+      }
+
+      const taxData = taxForms;
+      taxData.forEach(form => delete form.realName);
+      drawDiagram(taxData, 1000000, 100000);
+
+    </script>
+  </body>
+</html>

Exercise 8/bar-chart-with-labels.html

@@ -0,0 +1,109 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Tax forms: Bar chart with lines</title>
+    <meta charset="UTF-8">
+    <script src="taxForms.js"></script>
+  </head>
+  <body>
+
+    <canvas id="chart" width="700" height="550"></canvas>
+
+    <script>
+      const canvas = document.getElementById('chart');
+      const context = canvas.getContext('2d');
+
+      /* Draw a line from (fromX, fromY) to (toX, toY) */
+      function drawLine(fromX, fromY, toX, toY) {
+        context.beginPath();
+        context.moveTo(toX, toY);
+        context.lineTo(fromX, fromY);
+        context.stroke();
+      }
+
+      /* Draw a text (string) on (x, y) */
+      function drawText(text, x, y) {
+        context.fillStyle = 'black';
+        context.fillText(text, x, y);
+      }
+
+      /* Draw a text and with a line to its right */
+      function drawLineWithText(text, fromX, fromY, toX, toY) {
+        drawText(text, fromX - 50, fromY + 10);
+        drawLine(fromX, fromY, toX, toY);
+      }
+
+      /* Insert your code here. */
+
+      /**
+       * Draw lines on the y axis of the canvas
+       * 
+       * @param {number} n - Number of lines to draw
+       * @param {number} step - Number to add to y axis
+       */
+      const drawNLines = (n, step) => {
+        for (let i = 1; i <= n; i++) {
+          const y = canvas.height * (n - i + 1 ) / (n+1);
+          const text = step * i;
+          drawLineWithText(text, 50, y, canvas.width - 100, y);
+        }
+      }
+
+      /**
+       * Draws a rectangle onto the canvas
+       * 
+       * @param {number} x - x value of the upper left corner of the rectangle
+       * @param {number} y - y value of the upper left corner of the rectangle
+       * @param {number} width - Width of the rectangle
+       * @param {number} height - Height of the rectangle (DOWNWARDS)
+       * @param {string} color - Color of the rectangle
+       */
+      const drawRectangle = (x, y, width, height, color='red') => {
+        context.fillStyle = color;
+        context.fillRect(x, y, width, height);
+      }
+
+      /**
+       * Cycle a list of colors
+       * 
+       * @generator
+       * 
+       * @param {string[]} colors - List of colors to cycle
+       * @yields {string} A color
+       */
+      function* colorCycler(colors) {
+        let i = 0;
+        while (true) {
+          yield colors[i];
+          i = (i + 1) % colors.length;
+        }
+      }
+
+      /**
+       * Draw a legend on the canvas
+       * 
+       * @param {string[]} properties - An array of labels
+       * @param {[string[]} colorList - An array of colors to cycle when making labels
+       */
+      const drawLabels = (properties, colorList) => {
+        const colors = colorCycler(colorList);
+
+        const drawLabel = (text, color, y) => {
+          drawText(text, canvas.width-45, y + 15)
+          drawRectangle(canvas.width - 90, y, 40, 20, color);
+        }
+
+        const yOffset = canvas.height / 12
+        for (i in properties) {
+          drawLabel(properties[i], colors.next().value, yOffset+30*i);
+        }
+      }
+
+      drawNLines(10, 100000);
+      const taxData = taxForms;
+      taxData.forEach(form => delete form.realName);
+      drawLabels(Object.getOwnPropertyNames(taxData[0]), ['red', 'blue']);
+
+    </script>
+  </body>
+</html>

Exercise 8/bar-chart-with-lines.html

@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Tax forms: Bar chart with lines</title>
+    <meta charset="UTF-8">
+    <script src="taxForms.js"></script>
+  </head>
+  <body>
+
+    <canvas id="chart" width="700" height="550"></canvas>
+
+    <script>
+      const canvas = document.getElementById('chart');
+      const context = canvas.getContext('2d');
+
+      /* Draw a line from (fromX, fromY) to (toX, toY) */
+      function drawLine(fromX, fromY, toX, toY) {
+        context.beginPath();
+        context.moveTo(toX, toY);
+        context.lineTo(fromX, fromY);
+        context.stroke();
+      }
+
+      /* Draw a text (string) on (x, y) */
+      function drawText(text, x, y) {
+        context.fillStyle = 'black';
+        context.fillText(text, x, y);
+      }
+
+      /* Draw a text and with a line to its right */
+      function drawLineWithText(text, fromX, fromY, toX, toY) {
+        drawText(text, fromX - 50, fromY + 10);
+        drawLine(fromX, fromY, toX, toY);
+      }
+
+      /* Insert your code here. */
+
+      /**
+       * Draw lines on the y axis of the canvas
+       * 
+       * @param {number} n - Number of lines to draw
+       */
+      const drawNLines = (n) => {
+        for (let i = 1; i <= n; i++) {
+          const y = canvas.height * (n - i + 0.5) / n;
+          const text = 100000 * i;
+          drawLineWithText(text, 50, y, canvas.width, y);
+        }
+      }
+
+      drawNLines(10);
+
+    </script>
+  </body>
+</html>

Exercise 8/income-greater-than-500k.html

@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Income greather than 500 000</title>
+    <meta charset="UTF-8">
+    <script src="taxForms.js"></script>
+  </head>
+  <body>
+    <script>
+      console.log(taxForms.filter(form => form.income > 500000));
+    </script>
+  </body>
+</html>

Exercise 8/questions.txt

@@ -0,0 +1,46 @@
+# Questions
+
+1. When calling `getContext('2d')` on a Canvas element, it will return a drawing context (i.e. the type of canvas) - in this case a two-dimensional context. How can we get a three-dimensional context instead?
+
+You could use any version of WebGL. Webgl is an API for rendering graphics on the web, with the help of things like hardware acceleration and compiled function libraries which will run a lot faster than interpreting everything as javascript. Most modern browsers have an implementation of WebGL.
+
+Example of usage:
+```javascript
+  const ctx = canvas.getContext('webgl');
+```
+
+2. How would you create a blue circle using the Canvas element? Explain with words or code.
+
+```javascript
+  const drawCircle = (x, y, radius) => {
+    context.beginPath();
+    context.fillStyle('blue');
+    context.arc(x,y,0, Math.PI*2);
+    context.fill();
+  }
+
+  drawCircle();
+```
+
+3. What is a more terse (also known as shorter) way of writing the loop in the following usingthe Array.filter method?
+
+```javascript
+  const countries = ['Norway', 'Sweden',  'Denmark', 'New Zealand'];
+  const countriesStartingWithN = [];
+  
+  for (let i = 0; i < countries.length; i++) {
+    let country = countries[i];
+    if (country.startsWith('N')) {
+      countriesStartingWithN.push(country);
+    }
+  }
+```
+```javascript
+  const countries = ['Norway', 'Sweden',  'Denmark', 'New Zealand'];
+
+  const countriesStartingWithN = countries.filter(
+    country => country.startsWith('n')
+  );
+```
+
+[//]: # vim: set syntax=markdown:

Exercise 8/taxForms.js

@@ -0,0 +1,17 @@
+const taxForms = [
+  {
+    realName: "Bruce Wayne",
+    income: 750000,
+    wealth: 300000
+  },
+  {
+    realName: "John Blake",
+    income: 440000,
+    wealth: 832000
+  },
+  {
+    realName: "Selina Kyle",
+    income: 640000,
+    wealth: 432000
+  }
+];