移动元素到指定的位置

//HTML
<div id="test"></div>
//CSS
div{
      width:100px;
      height:100px;
      background:red;
}

//js
 /*将元素移动到300*300的位置*/
    var elem = document.getElementById("test");
    function moveElement(elementID,final_x,final_y,interval){
        var elem = document.getElementById(elementID);
        var xpos = parseInt(elem.style.left);
        var ypos = parseInt(elem.style.top);
        /*到达目的地left:300,top:300则退出函数*/
        if(xpos==final_x && ypos ==final_y) {
            return true;
        }
        /*小于300，加加*/
        if(xpos<final_x){
            xpos++;
        }else if(xpos>final_x){
            xpos--;
        }
        if(ypos<final_y){
            ypos++;
        }else if(ypos>final_y){
            ypos--;
        }
        elem.style.left = xpos+"px";
        elem.style.top = ypos+"px";
        var repeat = "moveElement("+"'"+elementID+"'"+","+final_x+","+final_y+","+interval+")";
        movement = setTimeout(repeat,interval);
    }
    function positionMessage(){
        elem.style.left="460px";
        elem.style.top="500px";
        elem.style.position="absolute";
        moveElement("test",300,300,10)

    }
    positionMessage();