var oDiv= document.getElementById("div");
oDiv.οnmοusedοwn= function(e){
var _this = this;
var e= e || window.event;
var diffX= e.clientX - _this.offsetLeft;
var diffY= e.clientY - _this.offsetTop;
if(_this.setCapture) _this.setCapture();
document.οnmοusemοve= function(e){
var e= e || window.event;
var left = e.clientX -diffX;
var top= e.clientY -diffY;
left= left < 0 ? 0 : left;
left= left > document.documentElement.clientWidth - _this.offsetWidth ? document.documentElement.clientWidth - _this.offsetWidth : left;
top= top < 0 ? 0 : top;
top= top > document.documentElement.clientHeight - _this.offsetHeight ? document.documentElement.clientHeight - _this.offsetHeight : top;
_this.style.left= left + "px";
_this.style.top= top + "px";
}
document.οnmοuseup= function(e){
this.οnmοusemοve= null;
this.οnmοuseup= null;
if(_this.releaseCapture) _this.releaseCapture();
}
}