flag = false;
window.document.onmousemove = dragImg;
window.document.onmouseup   = dragOff;
function dragOn(n)
{
	flag = true;
	iName = n;
	offx = event.x - document.images[iName].style.pixelLeft;
	offy = event.y - document.images[iName].style.pixelTop;
}
function dragOff(){ flag = false; }
function dragImg()
{
	if (!flag) return;
	document.images[iName].style.pixelTop  = event.y - offy;
	document.images[iName].style.pixelLeft = event.x - offx;
	return false;
}