(function($) {

    $.fn.shadowEnable  = function() { return $(this).find("+ .fx-shadow").show().end();   };
    $.fn.shadowDisable = function() { return $(this).find("+ .fx-shadow").hide().end();   };
    $.fn.shadowDestroy = function() { return $(this).find("+ .fx-shadow").remove().end(); };

    $.fn.shadow = function(options) {
        options = $.extend({
            offset:  1,
            opacity: 0.2,
            color:   "#000",
            monitor: false
        }, options || {});
        options.offset -= 1;

        return this.each(function() {

            // Remove an existing shadow if it exists
            var $element = $(this).shadowDestroy(),

            // Create a shadow element
            $shadow = $("<div class='fx-shadow' style='position: relative;'></div>").insertAfter($element);

            // Figure the base height and width
            baseWidth  = $element.outerWidth(),
            baseHeight = $element.outerHeight(),

            // Get the offset
            position = $element.position(),

            // Get z-index
            zIndex = parseInt($element.css("zIndex")) || 0;

            // Append smooth corners
            $('<div class="fx-shadow-color fx-shadow-layer-1"></div>').css({ position: 'absolute', opacity: options.opacity - 0.05,  left: options.offset,     top: options.offset,     width: baseWidth + 1, height: baseHeight + 1 }).appendTo($shadow);
            $('<div class="fx-shadow-color fx-shadow-layer-2"></div>').css({ position: 'absolute', opacity: options.opacity - 0.10,  left: options.offset + 2, top: options.offset + 2, width: baseWidth,     height: baseHeight - 3 }).appendTo($shadow);
            $('<div class="fx-shadow-color fx-shadow-layer-3"></div>').css({ position: 'absolute', opacity: options.opacity - 0.10,  left: options.offset + 2, top: options.offset + 2, width: baseWidth - 3, height: baseHeight     }).appendTo($shadow);
            $('<div class="fx-shadow-color fx-shadow-layer-4"></div>').css({ position: 'absolute', opacity: options.opacity,         left: options.offset + 1, top: options.offset + 1, width: baseWidth - 1, height: baseHeight - 1 }).appendTo($shadow);

            // Add color
            $("div.fx-shadow-color", $shadow).css("background-color", options.color);

            // Set zIndex +1 and make sure position is at least relative
            // Attention: the zIndex will get one higher!
            $element
                .css({
                    zIndex: zIndex + 1,
                    position: ($element.css("position") == "static" ? "relative" : "")
                });

            // Copy the original z-index and position to the clone
            // alert(shadow); If you insert this alert, opera will time correctly!!
            $shadow.css({
                position:     "absolute",
                zIndex:       zIndex,
                top:          position.top+"px",
                left:         position.left+"px",
                width:        baseWidth,
                height:       baseHeight,
                marginLeft:   $element.css("marginLeft"),
                marginRight:  $element.css("marginRight"),
                marginBottom: $element.css("marginBottom"),
                marginTop:    $element.css("marginTop")
            });


            if ( options.monitor ) {
                function rearrangeShadow() {
                    var $element = $(this), $shadow = $element.next();
                    // $shadow.css( $element.position() );
                    $shadow.css({
                        top:  parseInt($element.css("top"))  +"px",
                        left: parseInt($element.css("left")) +"px"
                    })
                    $(">*", $shadow).css({ height: this.offsetHeight+"px", width: this.offsetWidth+"px" });
                }

                // Attempt to use DOMAttrModified event
                $element.bind("DOMAttrModified", rearrangeShadow);

                // Use expressions if they exist (IE)
                if( $shadow[0].style.setExpression ) {
                    $shadow[0].style.setExpression("top" , "parseInt(this.previousSibling.currentStyle.top ) + 'px'");
                    $shadow[0].style.setExpression("left", "parseInt(this.previousSibling.currentStyle.left) + 'px'");
                }
            }

        });
    };

})(jQuery);