jQuery CSS bug in IE8

this should help.

it links to jquery ticket 2462 which is also interesting

Edit first link dead, wayback machine to the rescue.

And, just in case archive.org ever packs up, here is the contents of the dextrose blog post.

jQuery (at least up till version 1.2.6) has a problem with Internet Explorer when asking the background-position of an object.

$('h1:first').css('background-position');

In the other A-grade browsers, you get 2 values (in px or %) representing respectively the x-position and y-position of the element. In Internet Explorer (6 and 7) you get undefined. The problem is that IE doesn't know what background-position is, it only knows 2 other calls: background-position-x and background-position-y. Here is a slice of JavaScript code to handle this problem.

(function($) {
  jQuery.fn.backgroundPosition = function() {
    var p = $(this).css('background-position');
    if(typeof(p) === 'undefined') 
        return $(this).css('background-position-x') 
               + ' ' + $(this).css('background-position-y');
    else return p;
  };
})(jQuery);

You can now use this jQuery plugin to get the background-position of an element:

$('h1:first').backgroundPosition();