jQuery : as Cross Browser Solution :: Traversing
- Traversing Introduction
- jQuery DOM Traversing and Filter Examples
- jQuery DOM Traversing and Filter Methods
| Traversing Introduction |
jQuery is a very powerful tool which provides a variety of DOM traversal methods to help us select elements in a document randomly as well as in sequential method.
Most of the DOM Traversal Methods do not modify the jQuery object and they are used to filter out elements from a document based on given conditions.
Find Elements by index
Consider a Basic document as below.
<html>
<head>
<title>The JQuery Example</title>
</head> <body>
<div>
<ul>
<li>First option</li>
<li>Second option</li>
<li>Third option</li>
<li>Fourth option</li>
<li>Fifth option</li>
<li>Sixth option</li>
</ul>
</div>
</body>
</html>
Result
- First option
- Second option
- Third option
- Fourth option
- Fifth option
- Sixth option
Above every list has its own index, and can be located directly by using eq(index) method as below example.
Every child element starts its index from zero, thus, list item 2 would be accessed by using $(“li”).eq(1) and so on.
| jQuery DOM Traversing and Filter Examples |
Lets have color to list item having index 2.
<html>
<head>
<title>The JQuery Example</title>
<script type = "text/javascript"
src = "http://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js">
</script> <script type = "text/javascript">
$(document).ready(function() {
$("li").eq(2).addClass("selected");
});
</script>
<style>
.selected { color:gold; }
</style>
</head>
<body>
<div>
<ul>
<li class = "top">First option</li>
<li class = "top">Second option</li>
<li class = "middle">Third option</li>
<li class = "middle">Fourth option</li>
<li class = "bottom">Fifth option</li>
<li class = "bottom">Sixth option</li>
</ul>
</div>
</body>
</html>
Result
- First option
- Second option
- Third option
- Fourth option
- Fifth option
- Sixth option
Filtering out Elements
The filter( selector ) method can be used to filter out all elements from the set of matched elements that do not match the specified selector(s). The selector can be written using any selector syntax.
Example which applies color to the lists associated with middle class.
<html>
<head>
<title>The JQuery Example</title>
<script type = "text/javascript"
src = "http://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js">
</script> <script type = "text/javascript">
$(document).ready(function() {
$("li").filter(".middle").addClass("selected");
});
</script>
<style>
.selected { color:gold; }
</style>
</head>
<body>
<div>
<ul>
<li class = "top">First option</li>
<li class = "top">Second option</li>
<li class = "middle">Third option</li>
<li class = "middle">Fourth option</li>
<li class = "bottom">Fifth option</li>
<li class = "bottom">Sixth option</li>
</ul>
</div>
</body>
</html>
Result
- First option
- Second option
- Third option
- Fourth option
- Fifth option
- Sixth option
Locating descendant Elements
The find( selector ) method can be used to locate all the descendant elements of a particular type of elements. The selector can be written using any selector syntax.
Example for selects all the <span> elements available inside different <p> elements.
<html>
<head>
<title>The JQuery Example</title>
<script type = "text/javascript"
src = "http://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js">
</script>
<script type = "text/javascript">
$(document).ready(function() {
$("p").find("span").addClass("selected");
});
</script>
<style>
.selected { color:gold; }
</style>
</head>
<body>
<p>This is paragraph1 and <span>THIS IS GOLD COLOR</span>
</p> <p>This is paragraph2 and <span>THIS IS ALSO GOLD COLOR</span></p>
</body>
</html>
Result
This is paragraph1 and THIS IS GOLD COLOR
This is paragraph2 and THIS IS ALSO GOLD COLOR
| jQuery DOM Traversing and Filter Methods |
JQuery DOM Traversing Methods
List of methods which you can use to locate various elements in a DOM
| Methods | Description |
|---|---|
| add( selector ) | Adds more elements, matched by the given selector, to the set of matched elements. |
| andSelf( ) | Add the previous selection to the current selection. |
| children( [selector]) | Get a set of elements containing all of the unique immediate children of each of the matched set of elements. |
| closest( selector ) | Get a set of elements containing the closest parent element that matches the specified selector, the starting element included. |
| contents( ) | Find all the child nodes inside the matched elements (including text nodes), or the content document, if the element is an iframe. |
| end( ) | Revert the most recent ‘destructive’ operation, changing the set of matched elements to its previous state. |
| find( selector ) | Searches for descendant elements that match the specified selectors. |
| next( [selector] ) | Get a set of elements containing the unique next siblings of each of the given set of elements. |
| nextAll( [selector] ) | Find all sibling elements after the current element. |
| offsetParent( ) | Returns a jQuery collection with the positioned parent of the first matched element. |
| parent( [selector] ) | Get the direct parent of an element. If called on a set of elements, parent returns a set of their unique direct parent elements. |
| parents( [selector] ) | Get a set of elements containing the unique ancestors of the matched set of elements (except for the root element). |
| prev( [selector] ) | Get a set of elements containing the unique previous siblings of each of the matched set of elements. |
| prevAll( [selector] ) | Find all sibling elements in front of the current element. |
| siblings( [selector] ) | Get a set of elements containing all of the unique siblings of each of the matched set of elements. |
JQuery DOM Filter Methods
Lists of useful methods which you can use to filter out various elements from a list of DOM elements.
| Methods | Description |
|---|---|
| eq( index ) | Reduce the set of matched elements to a single element. |
| filter( selector ) | Removes all elements from the set of matched elements that do not match the specified selector(s). |
| filter( fn ) | Removes all elements from the set of matched elements that do not match the specified function. |
| is( selector ) | Checks the current selection against an expression and returns true, if at least one element of the selection fits the given selector. |
| map( callback ) | Translate a set of elements in the jQuery object into another set of values in a jQuery array (which may, or may not contain elements). |
| not( selector ) | Removes elements matching the specified selector from the set of matched elements. |
| slice( start, [end] ) | Selects a subset of the matched elements. |
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