I see you’re trying to link to a javascript file from a javascript file. You should totally drop that and try jQuery, a lightweight free library for Javascript.
With that, you can just do it like this:
$.getScript("myscript.js",function(){
alert("script has been loaded!")
});
Alternatively, you can append scripts to the end of your body, but this can cause some serious problems
But seriously, why not just load this in your HTML?
solved How to i link a script to a script? [duplicate]