What is my script src URL?

Is there a simple and reliable way to determine the URL of the currently-executing JavaScript file (inside a web page)?

My only thought on this is to scan the DOM for all the script src attributes to find how the current file was referenced and then figure out the absolute URL by applying it to document.location. Anyone have other ideas, is there some super-easy method I completely overlooked?

UPDATE: Script elements accessed via the DOM already have a src property which contains the full URL. I don't know how ubiquitous/standard that is, but alternatively you can use getAttribute("src") which will return whatever raw attribute value is in the [X]HTML.

Put this in the js file that needs to know it's own url.

Fully Qualified (eg http://www.example.com/js/main.js):

var scriptSource = (function(scripts) {
    var scripts = document.getElementsByTagName('script'),
        script = scripts[scripts.length - 1];

    if (script.getAttribute.length !== undefined) {
        return script.src
    }

    return script.getAttribute('src', -1)
}());

Or As it appears in source (eg /js/main.js):

var scriptSource = (function() {
    var scripts = document.getElementsByTagName('script'),
        script = scripts[scripts.length - 1];

    if (script.getAttribute.length !== undefined) {
        return script.getAttribute('src')
    }

    return script.getAttribute('src', 2)
}());

See http://www.glennjones.net/Post/809/getAttributehrefbug.htm for explanation of the getAttribute parameter being used (it's an IE bug).

For recent browsers, you can use document.currentScript to get this information.

var mySource = document.currentScript.src;

The upside is that it's more reliable for scripts that are loaded asynchronously. The downside is that it's not, as best I know, universally supported. It should work on Chrome >= 29, FireFox >= 4, Opera >= 16. Like many useful things, it doesn't seem to work in IE.

When I need to get a script path, I check to see if document.currentScript is defined, and, if not, use the method described in the accepted answer.

if (document.currentScript) {
    mySource = document.currentScript.src;
} else {
    // code omitted for brevity
}

https://developer.mozilla.org/en-US/docs/Web/API/document.currentScript