GDI-Intro-to-JavaScript/class2.html at master · lvecchio/GDI-Intro-to-JavaScript · GitHub

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<!doctype html>

<head>

<title>Class 2 ~ Javascript ~ Girl Develop IT</title>

The course is meant to be taught in 4 two-hour sections. Each of the slides and practice files are customizable according to the needs of a given class or audience.">

<link rel="stylesheet" href="reveal/lib/css/dark.css">

<!--[if lt IE 9]>

<![endif]-->

</head>

<body>

<h3>Beginning Javascript</h3>

<h4>Class 2</h4>

</section>

<h3>Welcome!</h3>

<p>Girl Develop It is here to provide affordable and accessible programs to learn software through mentorship and hands-on instruction.</p>

<p class ="green">Some "rules"</p>

<ul>

<li>Every question is important</li>

<li>Help each other</li>

</ul>

</div>

</section>

<h3>Loops</h3>

<p>Sometimes you want to go through a piece of code multiple times</p>

<ul>

<li class = "fragment">Showing a timer count down</li>

<li class = "fragment">Displaying the results of a search</li>

<li class = "fragment">Adding images to a slideshow</li>

</ul>

</section>

<h3>The while loop</h3>

<p>The while loop tells JS to repeat statements while a condition is true:</p>

while (expression) {

// statements to repeat

}

</code></pre>

var x = 0;

while (x < 5) {

console.log(x);

x++;

}

</code></pre>

Review: '++' means increment by 1!

</div>

<div class = "yellow">Danger!!</div>

<p>What happens if we forget x++;?</p>

<p>The loop will never end!!</p>

</div>

</section>

<p>The for loop is a safer way of looping</p>

for (initialize; condition; update) {

// statements to repeat

}

</code></pre>

for (var i = 0; i < 5; i++) {

console.log(i);

}

</code></pre>

Less danger of an infinite loop. All conditions are at the top!

</div>

</section>

<h3>Array</h3>

<p>An array is a data-type that holds an ordered list of values, of any type:</p>

var arrayName = [element0, element1, ...];

</code></pre>

</div>

var rainbowColors = ['Red', 'Orange', 'Yellow', 'Green', 'Blue', 'Indigo', 'Violet'];

var favoriteNumbers = [16, 27, 88];

var luckyThings = ['Rainbows', 7, 'Horseshoes'];

</code></pre>

</div>

The length property reports the size of the array:

console.log(rainbowColors.length);

</code></pre>

</div>

</section>

<h3>Arrays -- returning values</h3>

<p class = "fragment">You can access items with "bracket notation".</p>

The number inside the brackets is called an "index"

var arrayItem = arrayName[indexNum];

</code></pre>

</div>

Arrays in JavaScript are "zero-indexed", which means we start counting from zero.

var rainbowColors = ['Red', 'Orange', 'Yellow', 'Green', 'Blue', 'Indigo', 'Violet'];

var firstColor = rainbowColors[0];

var lastColor = rainbowColors[6];

</code></pre>

</div>

</section>

<h3>Arrays -- updating values</h3>

You can also use bracket notation to change the item in an array:

var awesomeAnimals = ['Corgis', 'Otters', 'Octopi'];

awesomeAnimals[0] = 'Bunnies';

</code></pre>

</div>

Or to add to an array:

awesomeAnimals[4] = 'Corgis';

</code></pre>

</div>

You can also use the push method:

awesomeAnimals.push('Ocelots');

</code></pre>

</div>

</section>

<h3>Loops and Arrays</h3>

Use a for loop to easily look at each item in an array:

var rainbowColors = ['Red', 'Orange', 'Yellow', 'Green', 'Blue', 'Indigo', 'Violet'];

for (var i = 0; i < rainbowColors.length; i++) {

console.log(rainbowColors[i]);

}

</code></pre>

</section>

<h3>Let's Develop It</h3>

<ul>

<li>Add a new link to the exercise from last week</li>

<li>Add an onclick to the link for a function called favoriteThings()</li>

<li>Create a new function called favoriteThings() in the javascript file</li>

<li>In the function, create an array and loop through the results</li>

<li>Post the results in an alert "My favorite things are XX, YY, ZZ'</li>

<li>Bonus -- add an 'and' in the sentence before the last item</li>

</ul>

</section>

<h3>Objects</h3>

<p>Objects are a data type that let us store a collection of properties and methods.</p>

var objectName = {

propertyName: propertyValue,

...

};

</code></pre>

var charlie = {

age: 8,

likes: ["baseball", "The little red-haired girl"],

pet: "Snoopy"

};

</code></pre>

</div>

</section>

<h3>Objects -- returning values</h3>

<p>Access values of "properties" using "dot notation":</p>

var charlie = {

age: 8,

likes: ["baseball", "The little red-haired girl"],

pet: "Snoopy"

};

</code></pre>

</div>

var pet = charlie.pet;

</code></pre>

</div>

</section>

<h3>Objects -- returning values</h3>

Or using "bracket notation" (like arrays):

var name = charlie['name'];

</code></pre>

</div>

Non-existent properties will return undefined:

var gender = charlie.gender

</code></pre>

</div>

</section>

<h3>Objects -- changing values</h3>

<p>Use dot or bracket notation with the assignment operator to change objects.</p>

Change existing properties:

charlie.name = "Chuck";

</code></pre>

</div>

Or add new properties:

charlie.gender = "male";

</code></pre>

</div>

You can also delete properties:

delete charlie.gender;

</code></pre>

</div>

</section>

<h3>Arrays of Objects</h3>

<p>Arrays can hold objects too!</p>

var peanuts = [

{name: "Charlie Brown",

pet: "Snoopy"},

{name: "Linus van Pelt",

pet: "Blue Blanket"}

];

</code></pre>

</div>

That means we can use a for loop!

for (var i = 0; i < peanuts.length; i++) {

var peanut = peanuts[i];

console.log(peanut.name + ' has a pet named ' + peanut.pet + '.');

}

</code></pre>

</div>

</section>

<h3>Objects in functions</h3>

<p>You can pass an object into a function as a parameter</p>

var peanut ={

pet: "Snoopy"

};

</code></pre>

function describeCharacter(character){

console.log(character.name + ' has a pet named ' + character.pet + '.');

}

</code></pre>

</div>

describeCharacter(peanut);

</code></pre>

</div>

</section>

<h3>Let's Develop It</h3>

<ul>

<li>Add another link that calls the function myFriends() onclick</li>

<li>Add a new function to the javascript myFriends</li>

<li>In the function, create an array of friends objects, with their names and hair colors</li>

<li>Use a for loop to go through each friend and describe them</li>

<li>Alert the results</li>

<li>Bonus -- make a separate functions that describe the friends</li>

</ul>

</section>

<ul>

<li class = "fragment">"Document Object Model"</li>

<li class = "fragment">A way to interact with the HTML elements on a webpage</li>

<li class = "fragment">Chrome and Firefox -- Right click --> Inspect Element</li>

</ul>

</section>

<h3>DOM Interaction</h3>

<p class = "fragment">On every webpage, the document object gives us ways of accessing and changing the DOM.</p>

<p class = "fragment left-align">Every DOM "node" has properties. They are connected like a family tree.</p>

<p class = "fragment left-align"> Parent (parentNode), children (childNodes, firstChild), siblings (prevSibling, nextSibling)</p>

var bodyNode = document.body; // <body>

var htmlNode = document.body.parentNode; // <html>

for (var i = 0; i < document.body.childNodes.length; i++) {

var childNode = document.body.childNodes[i];

//could be <p>, <h1>, etc.

//any html element

}

</code></pre>

</div>

</section>

<h3>DOM Interaction: Easier</h3>

<p class = "fragment blue">Finding every element on the page by siblings and children is time consuming!</p>

<p class = "fragment">The document object also provides methods for finding DOM nodes without going one by one</p>

Find element by id

</code></pre>

var img = document.getElementById('mainpicture');

</code></pre>

</div>

</section>

<h3>DOM Interaction: Easier</h3>

Find element by tag name (p, li, div, etc.)

<li class="peanut">Charlie Brown</li>

<li class="peanut">Linus van Pelt</li>

</code></pre>

var listItems = document.getElementsByTagName('li');

for (var i =0; i < listItems.length; i++) {

var listItem = listItems[i];

}

</code></pre>

</div>

</section>

<h3>Methods</h3>

<ul>

<li class = "fragment">Methods are functions that are associated with an object</li>

<li class = "fragment">The affect or return a value for a specific object</li>

<li class = "fragment">Used with dot notation</li>

</ul>

Previously seen example:

var img = document.getElementById('mainpicture');

</code></pre>

</div>

</section>

<h3>DOM Nodes -- Attributes</h3>

<p>We can use node methods to set and retrieve attributes</p>

getAttribute/setAttribute

var img = document.getElementById('mainpicture');

img.getAttribute('src');

img.setAttribute('src', 'http://girldevelopit.com/assets/pink-logo.png');

</code></pre>

var img = document.getElementById('mainpicture');

img.getAttribute('class');

img.setAttribute('class', 'picture-class');

</code></pre>

</div>

</section>

<h3>DOM innerHTML</h3>

<p>Each DOM node has an innerHTML property:</p>

document.body.innerHTML;

</code></pre>

</div>

You can set innerHTML yourself to change the contents of the node:

document.body.innerHTML = '<p>I changed the whole page!</p>';

</code></pre>

</div>

You can also just add to the innerHTML instead of replace everything:

document.body.innerHTML += "...just adding this bit at the end of the page.";

</code></pre>

</div>

</section>

<h3>DOM Modifying</h3>

<p>The document object can create new nodes:</p>

document.createElement(tagName);

document.createTextNode(text);

document.appendChild();

</code></pre>

</div>

var newImg = document.createElement('img');

newImg.src = 'http://girldevelopit.com/assets/pink-logo.png';

document.body.appendChild(newImg);

</code></pre>

</div>

var newParagraph = document.createElement('p');

var paragraphText = document.createTextNode('New Paragraph!');

newParagraph.appendChild(paragraphText);

document.body.appendChild(newParagraph);

</code></pre>

</div>

</section>

<h3>Let's Develop It</h3>

<ul>

<li>Put it all together</li>

<li>Modify your existing three functions to add new elements to the screen instead of fire an alert</li>

<li>Keep in mind how to find an element, how to append an element, and how to change the inner html of an element</li>

<li>There are lots of possible solutions! Be creative!</li>

</ul>

</section>

<h2>Questions?</h2>

<div style = "font-size:1200%; height:100%; margin-top:40%" class ="blue">?

</section>

</div>

Javascript ~ Girl Develop It ~

</div>

</footer>

</div>

// Full list of configuration options available here:

// https://github.com/hakimel/reveal.js#configuration

Reveal.initialize({

controls: true,

progress: true,

history: true,

theme: Reveal.getQueryHash().theme, // available themes are in /css/theme

transition: Reveal.getQueryHash().transition || 'default', // default/cube/page/concave/zoom/linear/none

// Optional libraries used to extend on reveal.js

dependencies: [

{ src: 'reveal/lib/js/classList.js', condition: function() { return !document.body.classList; } },

{ src: 'reveal/plugin/markdown/showdown.js', condition: function() { return !!document.querySelector( '[data-markdown]' ); } },

{ src: 'reveal/plugin/markdown/markdown.js', condition: function() { return !!document.querySelector( '[data-markdown]' ); } },

{ src: 'reveal/plugin/highlight/highlight.js', async: true, callback: function() { hljs.initHighlightingOnLoad(); } },

{ src: 'reveal/plugin/zoom-js/zoom.js', async: true, condition: function() { return !!document.body.classList; } },

{ src: 'reveal/plugin/notes/notes.js', async: true, condition: function() { return !!document.body.classList; } }

]

});

</script>

</body>

</html>

GDI-Intro-to-JavaScript/class2.html at master · lvecchio/GDI-Intro-to-JavaScript · GitHub

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