Given a jQuery object that represents a set of DOM elements, the .prevAll() method searches through the predecessors of these elements in the DOM tree and construct a new jQuery object from the matching elements; the elements are returned in order beginning with the closest sibling.
The method optionally accepts a selector expression of the same type that we can pass to the $() function. If the selector is supplied, the elements will be filtered by testing whether they match it.
Consider a page with a simple list on it:
<ul> <li>list item 1</li> <li>list item 2</li> <li class="third-item">list item 3</li> <li>list item 4</li> <li>list item 5</li> </ul>
If we begin at the third item, we can find the elements which come before it:
$( "li.third-item" ).prevAll().css( "background-color", "red" );
The result of this call is a red background behind items 1 and 2. Since we do not supply a selector expression, these preceding elements are unequivocally included as part of the object. If we had supplied one, the elements would be tested for a match before they were included.
A string containing a selector expression to match elements against.
Locate all the divs preceding the last div and give them a class.
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>prevAll demo</title>
<style>
div {
width: 70px;
height: 70px;
background: #abc;
border: 2px solid black;
margin: 10px;
float: left;
}
div.before {
border-color: red;
}
</style>
<script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
<div></div>
<div></div>
<div></div>
<div></div>
<script>
$( "div:last" ).prevAll().addClass( "before" );
</script>
</body>
</html>
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