function qiehuan(num)
{
	for(var id = 0;id<=7;id++)
	{
		if(id==num)
		{
			document.getElementById("qh_con"+id).style.display="block";
			document.getElementById("mynav"+id).className="nav_on";
		}
		else
		{
			document.getElementById("qh_con"+id).style.display="none";
			document.getElementById("mynav"+id).className="";
		}
	}
}
function preview(oper)
{
if (oper < 10){
bdhtml=window.document.body.innerHTML;//获取当前页的html代码
sprnstr="<!--startprint"+oper+"-->";//设置打印开始区域
eprnstr="<!--endprint"+oper+"-->";//设置打印结束区域
prnhtml=bdhtml.substring(bdhtml.indexOf(sprnstr)+18); //从开始代码向后取html

prnhtml=prnhtml.substring(0,prnhtml.indexOf(eprnstr));//从结束代码向前取html
window.document.body.innerHTML=prnhtml;
window.print();
window.document.body.innerHTML=bdhtml;
} else{
window.print();
}
}
function doZoom(size)
{
var zoom = document.all ? document.all['zoom'] : document.getElementById('zoom');
zoom.style.fontSize = size + 'px';
}