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JavaScript: Enhancing the DOM

Choosing elements by HTML tag


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JavaScript: Enhancing the DOM

with Ray Villalobos
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  1. 2m 36s
    1. Welcome
      59s
    2. What you should know before watching this course
      50s
    3. Using the exercise files
      47s
  2. 24m 33s
    1. What is the Document Object Model (DOM)?
      3m 2s
    2. Navigating the DOM with developer tools
      8m 10s
    3. Testing JavaScript commands with the console
      5m 50s
    4. Communicating with the console through JavaScript
      7m 31s
  3. 31m 9s
    1. Selecting elements with getElementById
      4m 10s
    2. Choosing elements by HTML tag
      3m 20s
    3. Isolating elements by class name
      3m 12s
    4. Querying CSS to select elements
      4m 54s
    5. Working with named form elements
      3m 39s
    6. Understanding nodeType, nodeName, and nodeValue
      4m 30s
    7. Traversing up and down DOM nodes
      4m 40s
    8. Targeting node elements
      2m 44s
  4. 22m 25s
    1. Changing HTML attributes
      5m 25s
    2. Working with restricted attributes
      2m 49s
    3. Detecting data attributes
      3m 29s
    4. Controlling classes with the HTML5 classList
      3m 21s
    5. Targeting the attributes property
      1m 24s
    6. Using text content modifiers
      3m 42s
    7. Modifying elements as text
      2m 15s
  5. 14m 57s
    1. Creating and appending nodes
      4m 27s
    2. Controlling node insertions with insertBefore
      3m 17s
    3. Cloning and removing nodes
      4m 41s
    4. Replacing existing nodes
      2m 32s
  6. 26m 14s
    1. What we'll build
      2m 16s
    2. Adding a bubbling event listener
      4m 11s
    3. Creating and styling an overlay with JavaScript
      4m 39s
    4. Adding an image
      3m 48s
    5. Resizing images in the DOM
      2m 59s
    6. Centering an image
      2m 36s
    7. Handling clicks
      1m 29s
    8. Adjusting for scrolling
      1m 36s
    9. Detecting and adjusting for a window resize
      2m 40s
  7. 1m 49s
    1. Next steps
      1m 49s

Video: Choosing elements by HTML tag

Traditionally, the easiest way to get to an element is by ID, but you probably don't have an ID for every element in the DOM, or at least you probably shouldn't. If getElementsByID is the most popular way to access things, then getElementsByTagName is the next most popular. GetElementsByTagName lets you access elements by their HTML tags. It's super simple to use and returns an array. So, notice that there is an extra S here. So, althought it's different than getElementbyId, it can be used with it to create complex targets.

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JavaScript: Enhancing the DOM
2h 3m Intermediate Jun 10, 2013

Viewers: in countries Watching now:

The Document Object Model (DOM) is at the core of every HTML page. In order to develop dynamic HTML pages, a front-end developer needs to understand how JavaScript connects to and controls the DOM, allowing you to create, modify, delete, and edit existing page content. This course focuses on helping you understand the DOM elements, and shows the different ways JavaScript gives you access to them and makes it easier to work with the DOM. Author Ray Villalobos covers navigating the DOM, selecting elements, modifying HTML attributes, editing nodes, and much more.

Topics include:
  • What is the DOM?
  • Choosing and isolating elements
  • Traversing up and down DOM nodes
  • Changing HTML attributes
  • Modifying elements as text
  • Creating and appending nodes
  • Cloning and removing nodes
  • Adding a bubbling event listener
  • Adding and resizing images
  • Handling clicks
Subjects:
Developer Web Web Design Web Development
Software:
HTML JavaScript
Author:
Ray Villalobos

Choosing elements by HTML tag

Traditionally, the easiest way to get to an element is by ID, but you probably don't have an ID for every element in the DOM, or at least you probably shouldn't. If getElementsByID is the most popular way to access things, then getElementsByTagName is the next most popular. GetElementsByTagName lets you access elements by their HTML tags. It's super simple to use and returns an array. So, notice that there is an extra S here. So, althought it's different than getElementbyId, it can be used with it to create complex targets.

So let's take a look. So I'm going to come here to my documents and I'm going to pull up the console. So I'm going to hit Cmd+Option+I, and then I'm going to hit the Esc key. I'm on a Mac, so that would be Ctrl+Option+I on a PC. So from here I can type in something like documents get elements by tag name. And then ask for a specific tag. So I'll ask for the List Item tag, and hit Return. Notice that I get an array like element with a bunch of list items, and I can open them up right here individually. So I can tell that this is the Home element right here, this little Home link.

And if I get down further, I should see some other element. So this is an artist's photo, I scroll up you can see it. And actually I can select it from right here, I can tell that it's a little bit further down. So that's that photo right there. So, it grabbed every single list item in my document. And that's sort of useful but, it could be a little bit better because we can target a specific list item if one of its containers has an I.D. So, if I wanted to go to this section of featured artists, I'm going to hit on this magnifying glass and click on one of these.

Just so I can learn the pathway here. Here's the path. I know that this has an ID of featured artists. So I can combine the document, get element by ID, and ask for first the list of featured artists. And then, within that, ask for the getElements by tag name so that it returns only the list items within the ID of feature artists. So if I hit Return I get just the list of my artists. It's tough to keep on typing that so I'm going to put it in a variable called my node.

And then I'm going to copy this right here. So now, this is assigned to a variable that I can simply call by typing the name. To get to individual elements, you can use an array notation. So I can say, my node and then ask for a specific element, this happens to be the third artist. Remember that arrays are 0 index, so item 2 is actually the third item. So, I can also type it in in its longer form like this, gets me the same element. Every list element of the featured artists has an image tag underneath it. So, we can easily get to it using the first child attribute and we just type my node, the shortened version and type in .firstchild.

Now I have to make sure that I specify which node by typing in the array notation and then .first child. So being able to access node elements by tag name can be super handy, especially when you combine it with get element by id.

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