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JavaScript: Enhancing the DOM
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Working with named form elements


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JavaScript: Enhancing the DOM

with Ray Villalobos

Video: Working with named form elements

Selecting form elements is a little easier because forms can have and additional attribute called Name. Like with document images, the DOM provides a special object called document.forms. That's an array of form elements on the page. You can also get to any form element that has a name a little bit easier. So, let's take a look. I'm going to go over to my website, and I'll click on this Register page. Now from here, you can see that I have a form on the left side of this document. Let me pull up the developer tool by hitting Cmd+Option+I on a Mac, Ctrl+Alt+I on a PC.
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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

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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

Working with named form elements

Selecting form elements is a little easier because forms can have and additional attribute called Name. Like with document images, the DOM provides a special object called document.forms. That's an array of form elements on the page. You can also get to any form element that has a name a little bit easier. So, let's take a look. I'm going to go over to my website, and I'll click on this Register page. Now from here, you can see that I have a form on the left side of this document. Let me pull up the developer tool by hitting Cmd+Option+I on a Mac, Ctrl+Alt+I on a PC.

And then, I'm going to hit the Escape key to pull up the console, and I'll type in document.forms. Now, that gives me an array of all the forms in the current document. I've only got one form, so it's only returning one item. If I want to get into that element, I can say document forms and then the index. Since this is the first item, I'm going to use the index 0, because arrays are 0 indexed. Now, I can get to the elements within the form. Now, since the form itself has a name, you can get to the form directly using dot notation. So, instead of doing that, I can just simply do document.register. And if I hit Enter, I get to the same place, a little bit quicker. Now if you open this form up, you can see that a lot of these elements have name attributes.

So, for example, I can get to the 'my name' field by typing in document, register and then my name. You can easily change the form fields value with the value attribute. You really have to be careful with forms, because there's a possibility of two input fields having the same name. In that case, you're going to get back an array. Although its pretty easy to get form elements by name, you can also use a special function called "get element by name".

So, you can document.getelementsbyname, and then get to subscribe and the zeroth element. In that case, it returns the first Radio button which is right here. You can change which of these fields is selected by choosing the checked attribute. So, I'm going to choose the second element, which would be element one and then select the checked attribute, and set that to checked.

That chooses the second element. For popup lists, you can get to the select element with the name property. So, you can say something like document.register.reference, and that gets you to that item. If you want to pre-select an item, you can also do it directly by setting the valley to one of the existing values. So, if you look at this form, you can see that we have the Option of a friend, Facebook and Twitter. But this doesn't actually matter, what matters is the values of these fields. If I opened up the select field, we can see that here I have a value of friend, Facebook, or twitter. So, I can go to document, register, reference, and then set the value to Facebook.

That picks Facebook from this list. There's also a property called selected index, it returns the Option currently selected. So, instead of doing this, I can choose Document register reference, and then you selected index. That tells me that the third element is currently selected. Remember that this is an array index, so the second element is actually element number three. There's a lot more to working with forms, so if you get a chance check out my course on form processing and validation.

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