Setting the swf Base Directory in HTML

April 7, 2011

Have you ever completed a flash project and started testing it online only to realize that the swf is looking for assets either in a different directory than the one you specified? Or that the folder that you have all your media stored is not in a relative directory like it was when working on it locally?

The solution that I mustered up in the past was to create a flashvar called something like “mediafolder” and put that in the embed code. From there, I would go back into my actionscript code and make sure all external media had the passed “mediafolder” variable appended to the beginning of the url for each external asset and then republish my swf.

This always worked well, so I usually plan for this, but my latest project didn’t have that built in. When it came to testing and we realized that the media folder was going to be in a different location than the base swf file and it was supposed to launch soon, it was time to see if there was another alternative to the usual solution. That’s when I discovered the “base” attribute in the swf object embed code.

The “base” attribute is actually an href attribute that specifies a base URL for all relative URLs on a page. Traditionally, you should be able to put it in the head of an html page and have all links on a page link relative to the string specified in the base attribute. For this it’s just specified for the swf, which picks it up when passed as a param and picks up any external asset from that folder by default instead of the folder that the actual swf is in.

Here’s a sample of the swfobject embed code:

<script type="text/javascript"> 
	var flashvars = {};
	var params = {"base": "../project/subfolder/"};
	var attributes = {id: "Main", name: "Main"};
	swfobject.embedSWF("MainLoader.swf", "myAlternativeContent", "920", "550", "10.0.0", "expressInstall.swf", flashvars, params, attributes);
</script>

With the example above, any asset that the main swf is trying to load relative to itself can now be placed in “../project/subfolder” without having to change any actionscript and republishing your swf. This is a tip that has saved me hours of work and would have saved me even more time had I discovered it in the past.