Pass vars to JavaScript via the SRC attribute

Question

In my HTML file I have linked to the JS with:

src="myscript.js?config=true"

Can my JS directly read the value of this var like this?

alert (config);

This does not work, and the FireFox Error Console says "config is not defined". How do I read the vars passed via the src attribute in the JS file? Is it this simple?

Answer 1

<script>
var config=true;
</script>
<script src="myscript.js"></script>

You can't pass variables to JS the way you tried. SCRIPT tag does not create a Window object (which has a query string), and it is not server side code.

Answer 2

Yes, you can, but you need to know the exact script file name in the script :

var libFileName = 'myscript.js',
    scripts = document.head.getElementsByTagName("script"), 
    i, j, src, parts, basePath, options = {};

for (i = 0; i < scripts.length; i++) {
  src = scripts[i].src;
  if (src.indexOf(libFileName) != -1) {
    parts = src.split('?');
    basePath = parts[0].replace(libFileName, '');
    if (parts[1]) {
      var opt = parts[1].split('&');
      for (j = opt.length-1; j >= 0; --j) {
        var pair = opt[j].split('=');
        options[pair[0]] = pair[1];
      }
    }
    break;
  }
}

You have now an 'options' variable which has the arguments passed. I didn't test it, I changed it a little from http://code.google.com/p/canvas-text/source/browse/trunk/canvas.text.js where it works.