Is it bad to add jQuery multiple times on a page?

Question

I am in a situation where I have multiple ASCX files that are being added to an aspx page. Some of these files include the jQuery library. Depending on which ones are added the jQuery library may be included more than once.

I cannot add jQuery at the masterpage or some other level, it must be from the ASCX. The reasons for this are beyond the scope of this question, but if someone really wants an explanation I can provide one.

Is it bad to have jQuery added multiple times in an ASPX page? Is there a way to conditionally add a script to an ASCX page?

`I cannot add jQuery at the masterpage or some other level, it must be from the ASCX.` Second paragraph, first sentence. — Abe Miessler, Aug 18 '11 at 05:35

score 8 · Accepted Answer · edited May 23 '17 at 12:23

8

in your ascxs you can do

if (typeof jQuery == 'undefined') {   
   // load jquery 
   var script = document.createElement('script');
    script.type = "text/javascript";
    script.src = "path/to/jQuery";
    document.getElementsByTagName('head')[0].appendChild(script);
} else {
  //already loaded
}

ref: check if jquery has been loaded, then load it if false

edited May 23 '17 at 12:23

Community

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answered Aug 18 '11 at 05:30

Rafay

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This is correct. If the code to dynamically load jQuery is needed, original poster should ask for that as well. – Nicholas Head Aug 18 '11 at 05:33
@3nigma, how would I go about loading jQuery conditionally? – Abe Miessler Aug 18 '11 at 05:35

Joseph Silber · Answer 2 · 2012-10-04T14:40:47.603

7

You should not add jQuery more than once.

You can add it conditionally though:

<script>window.jQuery || document.write('<script src="js/jquery-1.8.2.min.js">\x3C/script>')</script>

This is how they to it in the html5boilerplate

edited Oct 04 '12 at 14:40

answered Aug 18 '11 at 05:34

Joseph Silber

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Is it bad to add jQuery multiple times on a page?

2 Answers2