JQ弹出框移动-插件分享~~~

(function($){

    // to track if the mouse button is pressed

    var isMouseDown    = false;

    // to track the current element being dragged

    var currentElement = null;

    // callback holders

    var dropCallbacks = {};

    var dragCallbacks = {};

    // bubbling status

    var bubblings = {};

    // global position records

    var lastMouseX;

    var lastMouseY;

    var lastElemTop;

    var lastElemLeft;

    // track element dragStatus

    var dragStatus = {};    

    // if user is holding any handle or not

    var holdingHandler = false;

    // returns the mouse (cursor) current position

    $.getMousePosition = function(e){

        var posx = 0;

        var posy = 0;

        if (!e) var e = window.event;

        if (e.pageX || e.pageY) {

            posx = e.pageX;

            posy = e.pageY;

        }

        else if (e.clientX || e.clientY) {

            posx = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft;

            posy = e.clientY + document.body.scrollTop  + document.documentElement.scrollTop;

        }

        return { 'x': posx, 'y': posy };

    };

    // updates the position of the current element being dragged

    $.updatePosition = function(e) {

        var pos = $.getMousePosition(e);

        var spanX = (pos.x - lastMouseX);

        var spanY = (pos.y - lastMouseY);

        $(currentElement).css("top",  (lastElemTop + spanY));

        $(currentElement).css("left", (lastElemLeft + spanX));

    };

    // when the mouse is moved while the mouse button is pressed

    $(document).mousemove(function(e){

        if(isMouseDown && dragStatus[currentElement.id] != 'false'){

            // update the position and call the registered function

            $.updatePosition(e);

            if(dragCallbacks[currentElement.id] != undefined){

                dragCallbacks[currentElement.id](e, currentElement);

            }

            return false;

        }

    });

    // when the mouse button is released

    $(document).mouseup(function(e){

        if(isMouseDown && dragStatus[currentElement.id] != 'false'){

            isMouseDown = false;

            if(dropCallbacks[currentElement.id] != undefined){

                dropCallbacks[currentElement.id](e, currentElement);

            }

            return false;

        }

    });

    // register the function to be called while an element is being dragged

    $.fn.ondrag = function(callback){

        return this.each(function(){

            dragCallbacks[this.id] = callback;

        });

    };

    // register the function to be called when an element is dropped

    $.fn.ondrop = function(callback){

        return this.each(function(){

            dropCallbacks[this.id] = callback;

        });

    };

    // disable the dragging feature for the element

    $.fn.dragOff = function(){

        return this.each(function(){

            dragStatus[this.id] = 'off';

        });

    };

    // enable the dragging feature for the element

    $.fn.dragOn = function(){

        return this.each(function(){

            dragStatus[this.id] = 'on';

        });

    };

    // set a child element as a handler

    $.fn.setHandler = function(handlerId){

        return this.each(function(){

            var draggable = this;

            // enable event bubbling so the user can reach the handle

            bubblings[this.id] = true;

            // reset cursor style

            $(draggable).css("cursor", "");

            // set current drag status

            dragStatus[draggable.id] = "handler";

            // change handle cursor type

            $("#"+handlerId).css("cursor", "move");    

            // bind event handler

            $("#"+handlerId).mousedown(function(e){

                holdingHandler = true;

                $(draggable).trigger('mousedown', e);

            });

            // bind event handler

            $("#"+handlerId).mouseup(function(e){

                holdingHandler = false;

            });

        });

    }

    // set an element as draggable - allowBubbling enables/disables event bubbling

    $.fn.easydrag = function(allowBubbling){

        return this.each(function(){

            // if no id is defined assign a unique one

            if(undefined == this.id || !this.id.length) this.id = "easydrag"+(new Date().getTime());

            // save event bubbling status

            bubblings[this.id] = allowBubbling ? true : false;

            // set dragStatus

            dragStatus[this.id] = "on";

            // change the mouse pointer

            $(this).css("cursor", "move");

            // when an element receives a mouse press

            $(this).mousedown(function(e){

                // just when "on" or "handler"

                if((dragStatus[this.id] == "off") || (dragStatus[this.id] == "handler" && !holdingHandler))

                    return bubblings[this.id];

                // set it as absolute positioned

                $(this).css("position", "absolute");

                // set z-index

                $(this).css("z-index", parseInt( new Date().getTime()/1000 ));

                // update track variables

                isMouseDown    = true;

                currentElement = this;

                // retrieve positioning properties

                var pos    = $.getMousePosition(e);

                lastMouseX = pos.x;

                lastMouseY = pos.y;

                lastElemTop  = this.offsetTop;

                lastElemLeft = this.offsetLeft;

                $.updatePosition(e);

                return bubblings[this.id];

            });

        });

    };

})(jQuery);