function hoverTab(tabData){
		tabData.className = "tab";
	}
	
	function outTab(tabData){
		tabData.className = "tab";
	}
	
	function executeTab(tabData){
		tabData.className = "tabactive";
		tabData.onmouseover=function(){};
		tabData.onmouseout=function(){};
	}
	
	
	function showTabData(idForDisplay){
		var tabPromise = document.getElementById('tab-promise'); 
		var tabEvolution = document.getElementById('tab-evolution');
		var tabProven = document.getElementById('tab-proven');
		
		var promisetab = document.getElementById('promisetab');
		var evolutiontab = document.getElementById('evolutiontab');
		var proventab = document.getElementById('proventab');
		
		tabPromise.style.display = "none";
		tabEvolution.style.display = "none";
		tabProven.style.display = "none";	
		
		promisetab.className = "tab";
		evolutiontab.className = "tab";
		proventab.className = "tab";
		 		
		if (idForDisplay == "promise"){	
			tabPromise.style.display = "block";
			executeTab(promisetab);
			//swap images
			document.aboutimage.src = "images/about_promise.jpg";
		}else if(idForDisplay == "evolution"){
			tabEvolution.style.display = "block";
			executeTab(evolutiontab);	
			document.aboutimage.src = "images/about_evolution.jpg";
		}else if(idForDisplay == "proven"){
			tabProven.style.display = "block";
			executeTab(proventab);
			document.aboutimage.src = "images/about_proven.jpg";
		}
		
 	}