matching file extension in the document via javascript

Question

This is continued from my original question (http://stackoverflow.com/questions/10133976/getelementsbytagname-specific-links-only) which I got resolved but now facing different issue.

I'm implementing Anarchy player on my site and problem is that script stores files outside the domain root so links to them are in format like ( http: // mysite.com/mod/file/download.php?file_guid=fileID) which is fine for the player, it still plays the file but I need to separate files by type.

Look at the javascript code below, "if(o.href.match(/.mov$|.mp4$|.m4v$|.m4b$|.3gp$/i)" part, if I understand it correctly it says if file extension is .mov, .mp4, etc. than include that player. But since link is not in standard format with file name and extension it does not recognize it. How to change that "if(o.href.match" to something that would distinguish what type of file it is? I can pull file full name with extension in text format via PHP code and maybe wrap it in or div and that use if...div.match(...? Link to video file is already inside div block id "video"

<div id="video">
        <a href="<?php echo $file_url;?>"></a>
        </div>

Here is javascript:

var all = document.getElementById ( "video" ).getElementsByTagName ( "a" );
        for (var i = 0, o; o = all[i]; i++) {
            if(o.href.match(/\.mov$|\.mp4$|\.m4v$|\.m4b$|\.3gp$/i) && o.className!="amplink") {

Thank you so much for any suggestions.

Answer 1

It's not always possible to decide upon the filetype of a file just by looking at the filename. A better approach is to look at the Content-Type header (in case of an HTTP resource) or the MIME-type (which is essentially the same thing).

It's still possible to send a bad Content-Type so perhaps there is a way to identify the filetype by looking at the first few bytes? I know PNG starts with a very obvious indicator.