Css动画小DEMO

div{

            position:absolute;  //使DIV块脱离文档流 
            transition:left 1s linear,top 1s linear;
        }

var target=document.getElementById("div");
          target.style.left="0px";
          target.style.top="0px";
          document.onmousedown = function(evt){     //鼠标按下事件
              target.style.left= evt.pageX+"px";
              target.style.top= evt.pageY+"px";
          }