function addHandler(whichEvent, whichObject, attachThis){

	if(document.addEventListener){

		whichObject.addEventListener(whichEvent, attachThis, 0);
	}
	else if(document.attachEvent){

		whichObject.attachEvent("on"+whichEvent, attachThis);
	}
}

function siteTabs() {

	if(document.getElementById('tab_nav'))
	{
		var tabNavDiv   = document.getElementById('tab_nav');
		var tabNavLinks = tabNavDiv.getElementsByTagName('a');
		var tab;
		var active_tab = 'tab1';
		
		for (var i = 0; i < tabNavLinks.length; i++) 
		{
			if(tabNavLinks[i].className == 'on')
			{
				active_tab = tabNavLinks[i].id.replace('-','');
				break;
			}
		}
		
		for (var i = 0; i < tabNavLinks.length; i++) 
		{
			tab = tabNavLinks[i].id.replace('-','');
			
			tabNavLinks[i].parentNode.className = (tab == active_tab) ? "tabs_active" : "tabs_inactive";
			
			if(document.getElementById(tab))
			{
				document.getElementById(tab).style.display = (tab == active_tab) ? "block" : "none";
			}
			
			tabNavLinks[i].onclick = function() 
			{
				tabAction(this.id);
			}
		}
	}
}

function tabAction(id) {
	
	if(document.getElementById('tab_nav'))
	{
		var tabNavDiv   = document.getElementById('tab_nav');
		var tabNavLinks = tabNavDiv.getElementsByTagName('a');
		var currentTab  = id.replace('-','');
		
		for (var i = 0; i < tabNavLinks.length; i++) 
		{	
			tab = tabNavLinks[i].id.replace('-','');
			
			if(document.getElementById(tab))
			{
				document.getElementById(tab).style.display = (currentTab == tab) ? 'block' : 'none';
			}
			
			tabNavLinks[i].parentNode.className = (currentTab == tab) ? "tabs_active" : "tabs_inactive";
		}
	}
}

addHandler('load',window,siteTabs);