Modify "src=" in <script> tags before loading--without jQuery

Question

Basically, I want to do this:

<script src=" path + '/jquery.js'"></script>

(Obviously that won't work.)

I have a standalone page loading external scripts with <script>, but the URL needs to be prefixed with the variable path (because the page is run on different servers in different environments). I easily get path from the URL which always ends with "?path=X" where X is the actual path.

If I had jQuery, I know I could use getScript() to dynamically load external .js files, but jQuery is one of the files I need to load! I don't need anything too complicated here, no need to worry about encoding or file-types, it's a fairly simple situation except for the changing servers.

is it not possible to just load jquery from a cdn? Or is that not an option? — cillierscharl
– cillierscharl, Commented Oct 29, 2012 at 18:58
Not an option, it might be loaded on a system without a real connection to the internet. — brentonstrine
– brentonstrine, Commented Oct 29, 2012 at 19:04
Shouldn't you also be checking if jQuery is already included, as to not break the page you are including your script on? or do you not care about that. — user400654
– user400654, Commented Oct 29, 2012 at 19:04
@KevinB It is a standalone page and I can't see any way that jQuery could already be included. I haven't included it. Am I missing something obvious? — brentonstrine
– brentonstrine, Commented Oct 30, 2012 at 16:46
@brentonstrine Sorry, i missed that it is a standalone page, not script. — user400654
– user400654, Commented Oct 30, 2012 at 17:07

A. Wolff · Accepted Answer · 2012-10-29 19:21:49Z

5

You need to use plain javascript if jquery not loaded. Something like that:

        var fileref=document.createElement('script');
          fileref.setAttribute("type","text/javascript");
          fileref.setAttribute("src", path + '/jquery.js');
          document.getElementsByTagName("head")[0].appendChild(fileref);
          fileref.onload = function(){alert('loaded')};

edited Oct 29, 2012 at 19:21

answered Oct 29, 2012 at 18:58

A. Wolff

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2 Comments

brentonstrine Over a year ago

is this asynchronous? or would i have to test to see when the jquery is finished loading?

A. Wolff Over a year ago

asynch by default if from other domain, if same domain should be sync i think, see my edit

adeneo · Accepted Answer · 2012-10-29 18:59:07Z

1

You can load JS files by inserting them into the head with javascript, and at the same you can use your variable for the path when setting the source attribute:

<script type="text/javascript">
    var script = document.createElement('script');
        script.type = 'text/javascript';
        script.async = true;
        script.src = path + '/jquery.js';
    var head = document.getElementsByTagName('head')[0];
        head.appendChild(script);
</script>

answered Oct 29, 2012 at 18:59

adeneo

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