var x = 50,y = 60;
var xin = true, yin = true;
var step = 0.2;
var delay = 10;
var obj=document.getElementById("dcwj");
var width= window.screen.availWidth;
var height = window.screen.availHeight;
function dcwj() {
var L=T=0;
//var R= document.body.clientWidth-obj.offsetWidth;
var R= width-obj.offsetWidth-35;
//var B = document.body.clientHeight-obj.offsetHeight;
var B = height-obj.offsetHeight-100;
obj.style.left = x + (document.documentElement.scrollLeft || document.body.scrollLeft) + "px";
obj.style.top = y + (document.documentElement.scrollTop || document.body.scrollTop) + "px";
x = x + step*(xin?1:-1);
if (x < L) { xin = true; x = L;}
if (x > R){ xin = false; x = R;}
y = y + step*(yin?1:-1);
if (y < T) { yin = true; y = T; }
if (y > B) { yin = false; y = B; }
}
var itl;
if(obj!=null){
itl = setInterval("dcwj()", delay);
}
function closediv(){
clearInterval(itl);
obj.style.display = "none";
}