//鼠标拖动地图漫游
var gDragApproved=false;
var gEventX=gEventY=0;
function pOnMove()
{
	if(event.button==1 && gDragApproved){
		var sx=event.clientX-gEventX;
		var sy=event.clientY-gEventY;
		gEventX=event.clientX;
		gEventY=event.clientY;
		self.scrollBy(-sx,-sy);
	}
	return false
}
function pOnDrag()
{
	if(event.button!=1) return;
	gDragApproved=true;
	gEventX=event.clientX;
	gEventY=event.clientY;
	document.onmousemove=pOnMove;
}
document.onmousedown=pOnDrag;