jQuery Regex Selector Plugin not Working

Question

Question. I've tried to add this old jQuery Regex Selector plugin but it doesn't seem to give me back the right tag. At least, it says undefined when I try to return any info on it. I hope to use this someday for a game so I can select dynamic tags and things like all the foreground elements.

$('#button').click(function() {
    var elm = $('img:regex(data:extension, png)');
    elm.each(function() { alert($(this).attr('alt')); });
});

But all I get back is undefined when I alert the elm I get back [object Object]

JSFiddle

Answer 1

From the documentation you linked to: (emphasis mine)

Additionally it allows you to query data strings added to elements via jQuery’s ‘data’ method:

// Add data property to all images (just an example);
$('img').each(function(){
    $(this).data('extension', $(this)[0].src.match(/\.(.{1,4})$/)[1]);
});

// Select all images with PNG or JPG extensions:
$('img:regex(data:extension, png|jpg)');

You would need to run both parts of that code, not just the second part. Your image in your example does not have a data attribute.

--EDIT--

Also, you don't need regex to get this functionality, just do this:

var elm = $('img[src$=png]');

Here's a fiddle