In this post, we are learning about
jQuery Reading Attribute Values.
jQuery lets we examine the values of attributes with the attr() function.
For example, if we have two
<img> elements in a page and want to read the alt attribute
of the first
<img> element, we can pass the name of the attribute to be read to the jQuery attr() function.
$("img:first").attr("alt")
In addition, jQuery provides a way of getting the elements from a jQuery wrapped set. We
might think that this would work.
However, the [0] syntax returns a browser element, not a jQuery wrapped element,
so the attr( ) function will not work here. An easy way of getting elements from a wrapped
set is to use the jQuery slice( ) function; slice(m, n) returns the elements m to n-1
of a wrapped set, so we can get the first element of a wrapped set like this.
$("img").slice(0, 1).attr("alt")
Below code example puts for see above Reading Attribute Values working.
jqscript.html
<html>
<head>
<title>
Reading an alt attribute
</title>
<script src="jquery-latest.js"></script>
<script type="text/javascript">
function getAlt() {
alert($("img").slice(0,
1).attr("alt"));
}
</script>
</head>
<body>
<h1>Reading an alt attribute</h1>
<img src="../../img/jquery-logo.png"
alt="This is an image of jQuery logo." />
<img src="../../img/jquery-logo.png"
alt="This is also an image of jQuery logo." />
<br>
<form>
<input type="button"
value="Get alt attribute"
onclick="getAlt( )"
</input>
</form>
</body>
</html>
Output:
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