var previousIndex = -1;
function setTab(index) {
	var reiterdiv = document.getElementById("tabs");
	var tabSpans = reiterdiv.getElementsByTagName("span");
	var noTabs = tabSpans.length;
	
	for (var i = 0; i < noTabs; i++) {
		var tabId = tabSpans[i].getAttribute('id');
		var tabNo = tabId.split('_')[1];
		var divId = 'tab' + tabNo;
		
		// current is selected tab
		if(tabNo == index){
			// set style of previous tab
			if(previousIndex == 0){
				setClass('tab_' + previousIndex,  'firstactive');
			}else{
				setClass('tab_' + previousIndex,  'rightactive');
			}
			 
			// set style of selected tab
			if(i == noTabs - 1){
				setClass(tabId,  'lastactive');
			}else{
				setClass(tabId,  'active');
			}
			
			// set page content
			if(i > 0) setStyle(divId, 'block');
			
		// current not selected
		}else{
			// first tab
			if(i == 0){
				setClass(tabId,  'first');
			}
			// last tab
			else if(i == noTabs - 1){
				setClass(tabId,  'last');
			}
			// other tab
			else{
				setClass(tabId,  '');
			}
			
			if(i > 0) setStyle(divId, 'none');
		}
		previousIndex = tabNo;
	}
	

}

function setClass(elementId, value){
	if (document.all){
		if(document.all[elementId] != null){
			document.all[elementId].className = value;
		}
	} else { 
		if(document.getElementById(elementId) != null){
			document.getElementById(elementId).setAttribute('class', value);
		}
	}
}

function setStyle(elementId, value){
	
	if (document.all) {
		if(document.all[elementId] != null){
			document.all[elementId].style.display = value;
		}
	} else {
		if(document.getElementById(elementId) != null){
			document.getElementById(elementId).setAttribute('style', 'display:'+value+';');
		}
	}
}

function setVisible(elementId, value){
	
	if (document.all) {
		if(document.all[elementId] != null){
			document.all[elementId].style.visibility = value;
		}
	} else {
		if(document.getElementById(elementId) != null){
			document.getElementById(elementId).setAttribute('style', 'visibility:'+value+';');
		}
	}
}