(function($) {

    var dropShadowZindex = 1;  //z-index counter

    $.fn.dropShadow = function(options) {
        // Default options
        var opt = $.extend({
            left: 4,
            top: 4,
            blur: 2,
            opacity: .5,
            color: "black",
            swap: false
        }, options);
        var jShadows = $([]);  //empty jQuery collection

        // Loop through original elements
        this.not(".dropShadow").each(function() {
            var jthis = $(this);
            var shadows = [];
            var blur = (opt.blur <= 0) ? 0 : opt.blur;
            var opacity = (blur == 0) ? opt.opacity : opt.opacity / (blur * 8);
            var zOriginal = (opt.swap) ? dropShadowZindex : dropShadowZindex + 1;
            var zShadow = (opt.swap) ? dropShadowZindex + 1 : dropShadowZindex;

            // Create ID for shadow
            var shadowId;
            if (this.id) {
                shadowId = this.id + "_dropShadow";
            }
            else {
                shadowId = "ds" + (1 + Math.floor(9999 * Math.random()));
            }

            // Modify original element
            $.data(this, "shadowId", shadowId); //store id in expando
            $.data(this, "shadowOptions", options); //store options in expando
            jthis
        .attr("shadowId", shadowId)
        .css("zIndex", zOriginal);
            if (jthis.css("position") != "absolute") {
                jthis.css({
                    position: "relative",
                    zoom: 1 //for IE layout
                });
            }

            // Create first shadow layer
            bgColor = jthis.css("backgroundColor");
            if (bgColor == "rgba(0, 0, 0, 0)") bgColor = "transparent";  //Safari
            if (bgColor != "transparent" || jthis.css("backgroundImage") != "none"
          || this.nodeName == "SELECT"
          || this.nodeName == "INPUT"
          || this.nodeName == "TEXTAREA") {
                shadows[0] = $("<div></div>")
          .css("background", opt.color);
            }
            else {
                shadows[0] = jthis
          .clone()
          .removeAttr("id")
          .removeAttr("name")
          .removeAttr("shadowId")
          .css("color", opt.color);
            }
            shadows[0]
        .addClass("dropShadow")
        .css({
            height: jthis.outerHeight(),
            left: blur,
            opacity: opacity,
            position: "absolute",
            top: blur,
            width: jthis.outerWidth(),
            zIndex: zShadow
        });

            // Create other shadow layers
            var layers = (8 * blur) + 1;
            for (i = 1; i < layers; i++) {
                shadows[i] = shadows[0].clone();
            }

            // Position layers
            var i = 1;
            var j = blur;
            while (j > 0) {
                shadows[i].css({ left: j * 2, top: 0 });           //top
                shadows[i + 1].css({ left: j * 4, top: j * 2 });   //right
                shadows[i + 2].css({ left: j * 2, top: j * 4 });   //bottom
                shadows[i + 3].css({ left: 0, top: j * 2 });       //left
                shadows[i + 4].css({ left: j * 3, top: j });       //top-right
                shadows[i + 5].css({ left: j * 3, top: j * 3 });   //bottom-right
                shadows[i + 6].css({ left: j, top: j * 3 });       //bottom-left
                shadows[i + 7].css({ left: j, top: j });           //top-left
                i += 8;
                j--;
            }

            // Create container
            var divShadow = $("<div></div>")
        .attr("id", shadowId)
        .addClass("dropShadow")
        .css({
            left: jthis.position().left + opt.left - blur,
            marginTop: jthis.css("marginTop"),
            marginRight: jthis.css("marginRight"),
            marginBottom: jthis.css("marginBottom"),
            marginLeft: jthis.css("marginLeft"),
            position: "absolute",
            top: jthis.position().top + opt.top - blur,
            zIndex: zShadow
        });

            // Add layers to container  
            for (i = 0; i < layers; i++) {
                divShadow.append(shadows[i]);
            }

            // Add container to DOM
            jthis.after(divShadow);

            // Add shadow to return set
            jShadows = jShadows.add(divShadow);

            // Re-align shadow on window resize
            $(window).resize(function() {
                try {
                    divShadow.css({
                        left: jthis.position().left + opt.left - blur,
                        top: jthis.position().top + opt.top - blur
                    });
                }
                catch (e) { }
            });

            // Increment z-index counter
            dropShadowZindex += 2;

        });  //end each

        return this.pushStack(jShadows);
    };


    $.fn.redrawShadow = function() {
        // Remove existing shadows
        this.removeShadow();

        // Draw new shadows
        return this.each(function() {
            var shadowOptions = $.data(this, "shadowOptions");
            $(this).dropShadow(shadowOptions);
        });
    };


    $.fn.removeShadow = function() {
        return this.each(function() {
            var shadowId = $(this).shadowId();
            $("div#" + shadowId).remove();
        });
    };


    $.fn.shadowId = function() {
        return $.data(this[0], "shadowId");
    };


    $(function() {
        // Suppress printing of shadows
        var noPrint = "<style type='text/css' media='print'>";
        noPrint += ".dropShadow{visibility:hidden;}</style>";
        $("head").append(noPrint);
    });

})(jQuery);