How do you check if a selector exists in jQuery?

Question

In Mootools, I'd just run if ($('target')) { ... }. Does if ($('#target')) { ... } in jQuery work the same way?

Answer 1

no, jquery always returns a jquery object regardless if a selector was matched or not. You need to use .length

if ( $('#someDiv').length ){

}

Answer 2

As the other commenters are suggesting the most efficient way to do it seems to be:

if ($(selector).length ) {
    // Do something
}

If you absolutely must have an exists() function - which will be slower- you can do:

jQuery.fn.exists = function(){return this.length>0;}

Then in your code you can use

if ($(selector).exists()) {
    // Do something
}

As answered here

Answer 3

Alternatively:

if( jQuery('#elem').get(0) ) {}

Answer 4

if you used:

jQuery.fn.exists = function(){return ($(this).length > 0);}
if ($(selector).exists()) { }

you would imply that chaining was possible when it is not.

This would be better

jQuery.exists = function(selector) {return ($(selector).length > 0);}
if ($.exists(selector)) { }

Answer 5

if($('#elem')[0]) {}

Answer 6

Yet another way:

$('#elem').each(function(){
  // do stuff
});