Javascript Reference - HTML DOM hasAttribute() Method
The hasAttribute() method returns true if the
specified attribute exists, otherwise it returns false.
Browser Support
 |
 |
 |
 |
 |
|
|---|---|---|---|---|---|
hasAttribute |
Yes | 9 | Yes | Yes | Yes |
Syntax
element.hasAttribute(attributename)
Parameters
| Parameter | Type | Description |
|---|---|---|
| attributename | String | Required. The name of the attribute to check |
Return Value
It returns a Boolean type value.
true if the element has attributes, otherwise false.
Example
The following code shows how to check if the button element has an onclick attribute.
<!DOCTYPE html>
<html>
<body>
<p id="demo"></p>
<button onclick="myFunction()">test</button>
<script>
function myFunction()<!--from w w w . j a v a2s . c o m-->
{
var btn=document.getElementsByTagName("BUTTON")[0];
var x=document.getElementById("demo");
x.innerHTML=btn.hasAttribute("onclick");
}
</script>
</body>
</html>
The code above is rendered as follows:
Example 2
The following code uses hasAttribute to
check the existence of an attribute.
<!DOCTYPE HTML>
<html>
<body>
<p id="textblock" class="Survey numbers">
This is a test. <!-- ww w .jav a 2 s . c o m-->
</p>
<pre id="results"></pre>
<script>
var elem = document.getElementById("textblock");
document.writeln("lang attribute: " + elem.hasAttribute("lang"));
elem.setAttribute("lang", "en-US");
document.writeln("Attr value is : " + elem.getAttribute("lang"));
elem.setAttribute("lang", "en-UK");
document.writeln("Value is now: " + elem.getAttribute("lang"));
</script>
</body>
</html>