//显示或隐藏层的函数,页面引用:<a class="noclick" href="javascript:void(0)"  onClick="displaySubs('sub0',this)"></a>
var subs_array = new Array();
var qa=document.getElementById("qalist");
var subs_num =qa.getElementsByTagName('dd').length;
for(n=0;n<subs_num;n++){
    subs_array[n]="sub"+n;
}

// 将你要隐藏的层的ID放到这个变量中
function displaySubs(the_sub,o){
  if (document.getElementById(the_sub).style.display==""){
	document.getElementById(the_sub).style.display = "none";
	o.className="noclick";	
	return;
  }
  for (i=0;i<subs_array.length;i++){
	var my_sub = document.getElementById(subs_array[i]);
	my_sub.style.display = "none";
	/*兼容FF的写法,ff中会将空格也算作一个节点*/
    var app=navigator.appName;
    var verStr=navigator.appVersion;
    if (app.indexOf('Netscape') != -1) {
        my_sub.previousSibling.previousSibling.firstChild.className="noclick";
    }
    else if (app.indexOf('Microsoft') != -1) {
        my_sub.previousSibling.firstChild.className="noclick";
    }	
  }
  document.getElementById(the_sub).style.display = "";
  o.className="click";
}