
var oBtn = document.getElementById("btn1");
var oDiv1 = document.getElementById("div1");
oBtn.onclick = function(){
starMove(500);
}
var timer = null;
function starMove(iTarget){
clearInterval(timer);
timer = setInterval(function(){
var speed = (iTarget - oDiv1.offsetLeft) / 8;
speed = speed > 0? Math.ceil(speed):Math.floor(speed);
if(oDiv1.offsetLeft==iTarget){
clearInterval(timer);
}else{
oDiv1.style.left = oDiv1.offsetLeft + speed + "px";
}
var oTxt1 = document.getElementById("txt1");
oTxt1.value += speed + "," + oDiv1.offsetLeft + "\n";
},30);
}