/*=====================ǰ̨µ¼º½==============================*/
function nav_chang(nav)
{
	document.getElementById("index_nav_1").className = "";
	document.getElementById("index_nav_2").className = "";
	document.getElementById("index_nav_3").className = "";
	document.getElementById("index_nav_4").className = "";
	document.getElementById("index_nav_5").className = "";
	
	document.getElementById(nav).className = "nav_current";		
	//document.getElementById(nav).target = "_self";
	//document.getElementById(nav).href = url;
}