JQ拖曳效果

图片拖拽效果，网上找的某位大神力作：

$(function(){
/*--------------拖曳效果----------------
*原理：标记拖曳状态dragging ,坐标位置iX, iY
*         mousedown:fn(){dragging = true, 记录起始坐标位置，设置鼠标捕获}
*         mouseover:fn(){判断如果dragging = true, 则当前坐标位置 - 记录起始坐标位置，绝对定位的元素获得差值}
*         mouseup:fn(){dragging = false, 释放鼠标捕获，防止冒泡}
*/
var dragging = false;
var iX, iY;
$("#drag").mousedown(function(e) {
dragging = true;
iX = e.clientX - this.offsetLeft;
iY = e.clientY - this.offsetTop;
this.setCapture && this.setCapture();
return false;
});
document.onmousemove = function(e) {
if (dragging) {
var e = e || window.event;
var oX = e.clientX - iX;
var oY = e.clientY - iY;
locationX=(507-oX)*3264/380;
locationY=oY*3264/380;
$("#drag").css({"left":oX + "px", "top":oY + "px"});
return false;
}
};
$(document).mouseup(function(e) {
dragging = false;
$("#drag")[0].releaseCapture();
e.cancelBubble = true;
})

})

html代码

<div style="height:100%;position:relative;margin:10px auto;width:507px">
<img src='' id="printimg" style='height:380px;position:absolute;top:0;right:0;'/>
<img src='${path}/style_cp/img/red.png' id="drag"
style='height:25px;width:25px;position:absolute;top:0;right:0;z-index:10;cursor:hand'/>
</div>