How to get the URL-string from an anchor with javascript regular expressions

I made a new PlugIn for WordPress, and I had to upload swf files for the PlugIn. I used the WordPress built-in uploader for this task.The uploader is able to upload swf files, and with the “Insert to Post” button, I can get an anchor from the uploader, what contained the URL of the uploaded file.

Now I had to get the URL of the file, to store it in a database.