检查jQuery中是否存在Attribute（'id'）

Question

How can I check if an attribute Id exists in jQuery?

I searched around and found that this should work:

if ($(this).attr('id').attr('id'))
{

}

I still get this error: TypeError: Object gauge1 has no method 'attr'

Answer 1

This itself will work:

if($(this).attr("id"))

Check existing jsfiddle on the issue: http://jsfiddle.net/rwaldron/wVqvr/4/

Answer 2

Just try it the old way

if (this.id) { 
    //do something
}

Answer 3

You can use the is method and the Has Attribute Selector :

if ($(this).is('[id]')) {

}

Answer 4

if ($(this).attr('id')){ alert(id); }

Answer 5

you could also just use the plain js object

if( this.id !== undefined && this.id.length > 0 ){
 //todo: use id
}

Answer 6

HTML:

<div class="hey"></div>
<div class="you" id="woah"></div>
<div id="results"></div>​

jQuery:

var id = $('div.hey').attr('id');
if (id) {
    // Have an id.
} else {
    // Don't have an id.
}

A fiddle: http://jsfiddle.net/NEVYT/