Fixed width for IE Select elements (< 9)

ieSelectFixedWidth.js

$(document).ready(function() {
    if ($.browser.msie && $.browser.version.charAt(0) < 9) myScript.ieSelectFixedWidth('select.mini, select.medium');
}

// ...

var myScript = {
    ieSelectFixedWidth: function(el) {
	$(el).each(function(k, v) {
	    var obj = $(v);

	    if (obj.length > 0) {
		var objWidth = obj.outerWidth(),
		    objContainerId = obj.attr('id') + '_options',
		    objContainer = $('<span id="' + objContainerId + '" class="ieSelectFixedWidthContainer" />').css('width', objWidth),
		    widthSet = false;

		obj.wrap(objContainer);

		obj.bind("click mousedown focusin", function () {
		    displaySelectOverlay();
		});
		
		obj.bind("blur change focusout", function() {
		    hideSelectOverlay();
		});

		function displaySelectOverlay() {
		    if (!widthSet) {
			obj.css({'position': 'relative', 'width': 'auto'});
			if (obj.outerWidth() < obj.parent().innerWidth()) {
			    obj.css('width', objWidth);
			    widthSet = true;
			}
		    }
		}

		function hideSelectOverlay() {
		    obj.css('width', objWidth);
		}
	    }
	});
    }
};

style.css

.ieSelectFixedWidthContainer {
    position: relative;
    overflow: hidden;
    display: inline-block;
}