//控制表格的展开和收缩
	function toggle_collapse(tbody){
		if (document.all(tbody).style.display == ""){
			document.all(tbody).style.display = "none";
			document.all(tbody + "_img").src = "../image/bbs/closed_yes.gif";
			document.all(tbody + "_img").title = "打开";
		}
		else{
			document.all(tbody).style.display = "";
			document.all(tbody + "_img").src = "../image/bbs/closed_no.gif";
			document.all(tbody + "_img").title = "关闭";
		}
	}