<script>
function md(){
d.style.display="";
d.setCapture();
d.onmouseup=d.onlosecapture=mu;
d.onmousemove=mv;
d.startX=event.clientX;
d.startY=event.clientY;
d.style.left=event.x;
d.style.top=event.y;
d.style.width=0;
d.style.height=0;
hjs.style.display="none";
}
function mu(){
d.releaseCapture();
d.style.display="none";
hjs.style.display="";
var x2=event.clientX;
var y2=event.clientY;
x=Math.min(d.startX,x2);
y=Math.min(d.startY,y2);
x1=Math.max(d.startX,x2);
y1=Math.max(d.startY,y2);
with(hjs.style){
left=x;
top=y;
width=x1-x;
height=y1-y;
}
}
function mv(){
var x2=event.clientX;
var y2=event.clientY;
x=Math.min(d.startX,x2);
y=Math.min(d.startY,y2);
x1=Math.max(d.startX,x2);
y1=Math.max(d.startY,y2);
with(d.style){
left=x;
top=y;
width=x1-x;
height=y1-y;
}
}
</script>
<body onmousedown=md() >
用鼠标开始画吧
<div style="border:#444 1px solid;position:absolute;overflow:hidden;background-Color:#eee;display:none;" id="d"></div>
<div style="border:#000 1px solid;position:absolute;overflow:hidden;background-Color:#000;display:none;" id="hjs"></div>
</body>