function openPage(a,tab){
	showIndicator(); // common.js
	setActiveTab(tab);
	var xmlHttpRequest = false;
	if(browserType.indexOf("MSIE 7") != -1){
		xmlHttpRequest = createXmlHttpRequestIE7(); // to be compatible with IE7
	}else{
		xmlHttpRequest = createXmlHttpRequest();
	}
	
   if (xmlHttpRequest.overrideMimeType) {
	  xmlHttpRequest.overrideMimeType('text/xml');
	}	
	xmlHttpRequest.open('GET',a.href,true);		
	xmlHttpRequest.onreadystatechange = function() {
		if(xmlHttpRequest.readyState == 4){				
			var pageContents = xmlHttpRequest.responseText;			
			setPage(pageContents);
		}
	}
	xmlHttpRequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded; charset=UTF-8");
	xmlHttpRequest.send(null);
	hideIndicator();
}

function setPage(pageContents){
	var contents  = document.getElementById("contents");
	contents.innerHTML = pageContents;
}

function setActiveTab(tab){
	var	activeTab = getActiveTab();
	if(activeTab != null){
		activeTab.className = "";
	}
	tab.className="activelink";
}

function getActiveTab(){
	var ul = document.getElementById("nav");
	var lis = ul.getElementsByTagName("li");
	for(i=0; i< lis.length; i++){
		var li = lis[i];
		if(li.className == "activelink"){
			return li;
		}
	}
	return null;
		
}