Access the html page URL and swf path from flash with as3

To get the url of the html page that contains the flash/swf file we need a little help from the browser. I’ve written about the following methods before, but they were in as2 with “Get current url to Flash swf using an External Interface call” and “Get Current URL and Query String Parameters to Flash in as2“. In as3, we’ll still need access to javascript in the form of ExternalInterface, so if you want to do this on a site that doesn’t allow javascript you’ll have to keep searching (or jump to the bottom for an alternative method). We don’t need to do anything with the javascript or have access to the pages source code, javascript just has to be enabled, and it works in every browser I have access to. All we do is call a javascript line from within the swf which gets the url in the browser, namely:
That is the javascript we need to call. But we do it from an externalInterface call like so:"window.location.href.toString")
or to make sure all browsers play nicely we can wrap it in a function in case the browser doesn’t want to execute that as a line, this seems to work more solidly:"function(){ return window.location.href.toString();}")
also note that we’re specifically applying the toString method, this is needed so the javascript actually executes something and can return it.

Other things you may want to do related to this is getting the query string variables form the url, which also uses externalInterface. You can also use this same method to get the domain, path, protocol, and even referrer. You could use some nice regex or substrings to find these from the full url, but it is already accessible. I can see a potential need for the speed to get the full url and then use internal code to cut it however I need it. But, I’m not convinced that using an external interface call takes that much time (but it’d be an interesting experiment to say the least).

You may want to find the url to the actual swf, and this doesn’t require javascript at all, the swf does know where it is even if it doesn’t know where it is embedded. We can use the loderInfo object and the url property. This returns the url to the swf file regardless of what page or even domain it is embedded on:

For ExternalInterface to work in IE you need valid classid and id attributes in the tag. This is one of the reasons I use swfobject to handle my embed codes. It takes care of the Internet Exploder.

If your set up fails it may be because it throws a security error. To solve this to set the param allowScriptAccess to ‘always’ and in your actionscript add your domain, in order to enable the use of ExternalInterface.

[cc lang=”html”]
[cc lang=”actionscript”]


get href url tutorial demo
This demo, gets all of the above mentioned values/properties and more. I threw in what I could think of that may be useful or interesting. It shows a couple ways to get the window location href as well as a way it won’t work. Then there are the rest of the properties available using this same method: href, host, hostname, hash (anchor link ‘#’), pathname (url after the domain), port, protocol, search (query string values), the document title and even referrer. Then from the loaderInfo object we can access the url of the swf as well as other things but most used is the bytesTotal and bytesLoaded. Now check out the demo here (adding an fpo hash and query string to the link just for demonstration purposes, feel free to play with the url and see the values updated.
[cc lang=”actionscript”]
import flash.external.ExternalInterface;

displayText.appendText(‘“function(){ return document.location.href.toString();}”): ‘ +“function(){ return document.location.href.toString();}”) + “\n”);
displayText.appendText(‘“function(){ return window.location.href.toString();}”): ‘ +“function(){ return window.location.href.toString();}”) + “\n”);
displayText.appendText(‘“window.location.href.toString”): ‘ +“window.location.href.toString”) + “\n”);
displayText.appendText(‘“window.location.href”): ‘ +“window.location.href”) + “\n”);
displayText.appendText(‘“”): ‘ +“”) + “\n”);
displayText.appendText(‘“window.location.hostname.toString”): ‘ +“window.location.hostname.toString”) + “\n”);
displayText.appendText(‘“window.location.hash.toString”): ‘ +“window.location.hash.toString”) + “\n”);
displayText.appendText(‘“window.location.pathname.toString”): ‘ +“window.location.pathname.toString”) + “\n”);
displayText.appendText(‘“window.location.port.toString”): ‘ +“window.location.port.toString”) + “\n”);
displayText.appendText(‘“window.location.protocol.toString”): ‘ +“window.location.protocol.toString”) + “\n”);
displayText.appendText(‘“”): ‘ +“”) + “\n”);

displayText.appendText(‘“function(){ return document.title;}”): ‘ +“function(){ return document.title;}”) + “\n”);
displayText.appendText(‘“function(){ return document.referrer;}”): ‘ +“function(){ return document.referrer;}”) + “\n”);

displayText.appendText(‘this.loaderInfo.url: ‘ + this.loaderInfo.url + “\n”);
displayText.appendText(‘this.loaderInfo.bytesLoaded: ‘ + this.loaderInfo.bytesLoaded + “\n”);
displayText.appendText(‘this.loaderInfo.bytesTotal: ‘ + this.loaderInfo.bytesTotal + “\n”);

Finally a method I’ve used in my video players when I want users to be able to share the link through the player is send an explicit ‘permalink’ in the flashvars or xml playlist. Then the video can be embedded on any site and users can share the original video url. Plus then I don’t have to rely on javascript. I’ve written about flashvars in the past though, so I’ll leave it to you to put 2 and 2 together. Flashvars is one more plug for swfobject to me though, because it makes it so I only have to declare them once and it handles all the browser specific code.

Anyways, this demo has been tested in mac firefox, chrome, safari and windows ie7, ie8, firefox and chrome. If you have a different browser please comment that it works (or not) so we can get a full spectrum, thanks!

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9 thoughts on “Access the html page URL and swf path from flash with as3

  1. Thanks a lot for this. I needed to get individual variable values from the query / search string. Found a nice JS script and converted it to AS3:
    if your browser would point to:

    you could use this script to retrieve myvar ‘s and mynum’s value like this:

    var hrefMyVar:String = getBrowserQueryVar(“myvar”);
    var hrefMyNumr:String = getBrowserQueryVar(“myvar”);

    with this script:

    public static function getBrowserQueryVar(getvar:String):String
    if (ExternalInterface.available) {
    var queryString:String =“”);
    var p = id;
    var regex:RegExp = new RegExp(“[?&]” + p + “(?:=([^&]*))?”,”i”);
    var match:Array = regex.exec(queryString);
    var value:String = null;
    if( match && match.length){ value = match[1]; }
    return value;
    return null;

    1. typo in this line, has to be “mynum”, not “myvar” as argument
      var hrefMyNumr:String = getBrowserQueryVar(“mynum”);

  2. I needed to store url variables from advertising tracking servers – this method works like a charm! Cheers:)

  3. Hey Thanks for help getting individual vars @latcho

    there is an another type … here is fixed function

    public static function getBrowserQueryVar(getvar:String):String {
    if (ExternalInterface.available) {
    //var p = id; // ID SHOULD BE GETVAR OR GETVAR SHOULD BE ID 🙂 any way its working
    var p = getvar;
    var regex:RegExp=new RegExp(“[?&]”+p+”(?:=([^&]*))?”,”i”);
    var match:Array=regex.exec(queryString);
    var value:String=null;
    if (match&&match.length) {
    return value;
    return null;

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