jquery plugin to appy AlphaImageLoader filter on transparent png images

ail-filter.js

/* global $, jQuery, window */

(function($) {

	/**
	 *
	 */
	function applyFilterOnBackgroundImage($node, sizingMethod) {
		var regex = /url\(["']*(.*?)["']*\)/;
		var src = $node.css("background-image").replace(regex, "$1");
		var sizing = (sizingMethod === undefined) ? 'image' : sizingMethod;
		if (src !== 'none') {
			$node.css({
				backgroundImage: "none",
				filter: 'progid:DXImageTransform.Microsoft.AlphaImageLoader(src="' + src + '", sizingMethod="' + sizing + '")'
			});
		} 
	}

	/**
	 *
	 */
	function applyFilterOnImage($node, sizingMethod) {
		var src = $node.attr('src');
		var sizing = (sizingMethod === undefined) ? 'image' : sizingMethod;
		if (src.indexOf('.png') !== -1) {
			$node.css({
				filter: 'progid:DXImageTransform.Microsoft.AlphaImageLoader(src="' + src + '", sizingMethod="' + sizing + '")'
			});
		}
	}

	/**
	 *
	 */
	function isImageElement($node) {
		var isImage, tagName;

		try {
			tagName = $node.get(0).tagName.toLowerCase();	
		} catch(error) {}

		isImage = (tagName === 'img');
		return isImage;
	}

	/**
	 *
	 */
	function applyFilter($node, sizingMethod) {
		if (isImageElement($node)) {
			applyFilterOnImage($node, sizingMethod);
		} else {
			applyFilterOnBackgroundImage($node, sizingMethod);
		}
	}

	/**
	 *
	 */
	function isLessThanIE9() {
		return (typeof window.addEventListener === 'undefined' && typeof document.getElementsByClassName === 'undefined');
	}
 

	/**
	 * @param sizingMethod:String 'image(default)', 'scale' or 'crop'
	 */
	$.fn.applyAILFilter = function(sizingMethod) {
		this.each(function() {
			applyFilter($(this), sizingMethod);
		});
		return this;
	}

})(jQuery);