How might I get the script filename from within that script?

Question

I'm pretty sure the answer is no, but thought I'd ask anyway.

If my site references a scripted named "whatever.js", is it possible to get "whatever.js" from within that script? Like:

var scriptName = ???

if (typeof jQuery !== "function") {
    throw new Error(
     "jQuery's script needs to be loaded before " + 
     scriptName + ". Check the <script> tag order.");
}

Probably more trouble than it's worth for dependency checking, but what the hell.

Answer 1

Since you are going to be typing that line into the file somewhere, couldn't you just type in the name of the file you're adding it to?

Answer 2

var scripts = document.getElementsByTagName('script');
var lastScript = scripts[scripts.length-1];
var scriptName = lastScript.src;
alert("loading: " + scriptName);

Tested in: FF 3.0.8, Chrome 1.0.154.53, IE6

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See also: How may I reference the script tag that loaded the currently-executing script?

Answer 3

You can return a list of script elements in the page:

var scripts = document.getElementsByTagName("script");

And then evaluate each one and retrieve its location:

var location;

for(var i=0; i<scripts.length;++i) {
   location = scripts[i].src;

   //Do stuff with the script location here
}

Answer 4

What will happen if the jQuery script isn't there? Are you just going to output a message? I guess it is slightly better for debugging if something goes wrong, but it's not very helpful for users.

I'd say just design your pages such that this occurrence will not happen, and in the rare event it does, just let the script fail.