phpjs/experimental/language/__FILE__.js

php.js offers community built php functions in javascript

function __FILE__() {
  // http://kevin.vanzonneveld.net
  // +   original by: Michael White (http://getsprink.com/)
  // +   improved by: Brett Zamir (http://brett-zamir.me)
  // %        note 1: Not a function in PHP, so in experimental
  // %        note 2: It will probably need a bit of work to make it fully
  // %        note 2: cross-browser
  // %        note 3: If the function thinks it is in the original HTML
  // %        note 3: document then the URL stored in this.window.location.href
  // %        note 3: is used. There might be a better choice for this.
  // *     example 1: __FILE__();
  // *     returns 1: 'http://example.com/myfile.js'

  var d = this.window.document;

  var t = d.getElementsByTagName('script');
  if (!t || t.length === 0) {
    t = d.getElementsByTagNameNS('http://www.w3.org/1999/xhtml', 'script');
  }
  var url = t[t.length - 1];

  if (url.hasAttribute('src')) { // Let work for XUL as well
    var src = url.getAttribute('src');
    if (src !== '' && /^(https?|chrome):/.test(src)) { // Must be absolute reference
      return src;
    }
  }
  return this.window.location.href;
}