The best way to know if JQuery is available?

Question

Possible Duplicate:
How to check if jQuery is loaded and what version?

What is the best way to check to see if JQuery is loaded?

What are you currently using? What issues are you facing with it? — Piskvor left the building, Nov 23 '11 at 12:22
@clamp: This *will* bite you - Prototype also uses `$`. `if (jQuery)` perhaps? — Piskvor left the building, Nov 23 '11 at 12:23

olistik · Accepted Answer · 2011-11-23T13:42:25.853

32

if (typeof jQuery === 'undefined') {
  // jQuery is NOT available
} else {
  // jQuery is available
}

edited Nov 23 '11 at 13:42

answered Nov 23 '11 at 12:26

olistik

734
5
13

1

This is completely backwards. -1 – Ryan Kinal Nov 23 '11 at 13:12
1

ops.. I've corrected, thanks for pointing that out :-) – olistik Nov 23 '11 at 13:43

Haim Evgi · Answer 2 · 2011-11-23T12:32:54.397

0

look on http://jquery-howto.blogspot.com/2009/03/check-if-jqueryjs-is-loaded.html

Method 1:

if (jQuery) {  
    // jQuery is loaded  
} else {
    // jQuery is not loaded
}

Method 2:

if (typeof jQuery == 'undefined') {  
    // jQuery is not loaded  
} else {
    // jQuery is loaded
}

in try catch

try
{
     var jqueryIsLoaded = jQuery;
     jQueryIsLoaded = true;
}
catch(err)
{
     var jQueryIsLoaded = false;
}

if(jQueryIsLoaded) 
{
}
else
{
}

edited Nov 23 '11 at 12:32

answered Nov 23 '11 at 12:22

Haim Evgi

120,002
45
212
219

2

Method1: reference error if not – jAndy Nov 23 '11 at 12:24
Can you combine this with a `try/catch`? – Xyan Ewing Nov 23 '11 at 12:27
@XyanEwing: you could, but it would be pretty bad/slow'ish. Much better is the usage of the `in operator`. `if( 'jQuery' in window ) {}` – jAndy Nov 23 '11 at 12:30
1

The try catch method combined with `typeof jQuery === 'undefined'` solved my issue – Clain Dsilva Dec 13 '21 at 10:22

The best way to know if JQuery is available?

2 Answers2

Linked