获得鼠标xy值

//获取坐标位置   function getPosition(ev){       ev = ev || window.event;       var point = {x:0,y:0};       if(ev.pageX || ev.pageY){           point.x = ev.pageX;           point.y = ev.pageY;       } else {//兼容ie           point.x = ev.clientX + document.body.scrollLeft - document.body.clientLeft;           point.y = ev.clientY + document.documentElement.scrollTop;       }       return point;       }