Question

I encountered a problem that took me some time to debug where a plug-in that I was using for jQuery (in this case jFeed) was not working. The problem ended up being because we also used Amazon Associates product previews. The product previews code ends up including a number of other JS files through document.write(), including another copy of jQuery. Because the product previews code appeared below the jFeed script, jQuery was redefined without the getFeed function.

Is there a best practice to ensure that certain objects like jQuery only get defined once on a page? I’m thinking of something like #ifndef with C/C++, but I don’t know how it would work in this case where I didn’t write the code that dynamically pulled in jQuery again.

Answer 1

I think in your situation, it would probably be best to redefine the jQuery variable as something else. The other jQuery code might use a different version so you might want to define a new variable which would indicate which jQuery you’re using.

You could so something like this:

 <script>
    var $jMain = jQuery;
 </script>

You would then just use the $jMain instead of jQuery or $. It’ll be up to you to you to ensure you have the correct jQuery object when you do this. Here’s the documentation.