Can code in a Javascript file know its own domain/URL

Question

If I have a site, example.com, and a page on that site references a Javascript at subdomain.example.com/serveAd.js -- is there a way from within serveAd.js to know its own URL, or the domain from which it was downloaded?

(The JS can certainly know all about the page that called it. I want to know if the JS knows about its own origin.)

Indeed, it's addressed similarly in other places. And the answers are similar to below, which are good ideas. Thanks! — Matt Sherman
– Matt Sherman, Commented Jun 23, 2010 at 4:44

laher · Accepted Answer · 2010-06-22 22:48:52Z

15

If you were using jquery, you could get the full url with this kind of thing:

var fullJsUrl= $('script[src$=serveAd.js]').attr('src');

If not using jquery, it may take more work, but you get the idea ;)

answered Jun 22, 2010 at 22:48

laher

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4 Comments

atmd Over a year ago

Not sure if this is due to the changes in jquery since this question, but now this only works for me with $('script[src$="serveAd.js"]').attr('src'); // quotes around the file name

user128511 Over a year ago

Without jquery document.querySelector('script[src$="serveAd.js"]).src

giuliolunati Over a year ago

@gman good response but there's a typo. Should be document.querySelector('script[src$="serveAd.js"]').src with the closing single quote

Peter Over a year ago

This will find the first script file which name ends with "serveAd.js". So this will fail if there is multiple scripts like that (such as a "dont-serveAd.js" before "serveAd.js"). It will also fail if the script has been renamed for some reason. (But this name was given in the question, so not a problem in this case.)

gnarf · Accepted Answer · 2010-06-22 22:40:52Z

6

I'm pretty sure, as the script is parsed that the last <script> node available in the DOM will be the one being parsed.

Try this in an external JS to see:

var scripts = document.getElementsByTagName('script');
var lastScript = scripts[scripts.length - 1];
alert(lastScript.src);

answered Jun 22, 2010 at 22:40

gnarf

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2 Comments

bart Over a year ago

Not if the script file was loaded using createElement/appendChild, then it could be anywhere in the DOM (depending on where you appended it to).

Peter Over a year ago

This will fail if the script is loaded async (which is becoming more popular).

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