图片的拖放

head中引用：
 
Html代码 
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script> 
 
实现拖动到js代码：
 
Js代码 
 <script type="text/javascript"> 
//           拖动 
//  jQuery.noConflict() 
 
 
var ddimagepanner={ 
 
    init:function($, $img, options){ 
        var s=options 
        s.imagesize=[$img.width(), $img.height()] 
        s.pos=(s.pos=="center")? [-(s.imagesize[0]/2-s.wrappersize[0]/2), -(s.imagesize[1]/2-s.wrappersize[1]/2)] : [center, center] //initial coords of image 
        s.pos=[Math.floor(s.pos[0]), Math.floor(s.pos[1])] 
        $img.css({position:'absolute', left:s.pos[0], top:s.pos[1]}) 
        s.dragcheck={h: (s.wrappersize[0]>s.imagesize[0])? false:true, v:(s.wrappersize[1]>s.imagesize[1])? false:true} 
        if (s.dragcheck.h==false && s.dragcheck.v==false) //if image shouldn't be pannable (container larger than image) 
            s.$pancontainer.css({cursor:'auto'}) 
        else 
            this.dragimage($, $img, s) 
    }, 
 
    dragimage:function($, $img, s){ 
        $img.mousedown(function(e){ 
            var imgoffset=$img.offset() 
            s.pos=[parseInt($img.css('left')), parseInt($img.css('top'))] 
            var xypos=[e.clientX, e.clientY] 
            $img.bind('mousemove.dragstart', function(e){ 
                var pos=s.pos 
                var dx=e.clientX-xypos[0] //distance to move horizontally 
                var dy=e.clientY-xypos[1] //vertically 
                if (s.dragcheck.h==true) //allow dragging horizontally? 
                    var newx=(dx>0)? Math.min(0, s.pos[0]+dx) : Math.max(-s.imagesize[0]+s.wrappersize[0], s.pos[0]+dx) //Set horizonal bonds. dx>0 indicates drag right versus left 
                if (s.dragcheck.v==true) //allow dragging vertically? 
                    var newy=(dy>0)? Math.min(0, s.pos[1]+dy) : Math.max(-s.imagesize[1]+s.wrappersize[1], s.pos[1]+dy) //Set vertical bonds. dy>0 indicates drag downwards versus up 
                $img.css({left:(typeof newx!="undefined")? newx : s.pos[0], top:(ty