var currentTab = 0;
	
	function getNumberOfTabs() {
			listOfTabs = document.getElementById('picturesalbum').getElementsByTagName('div');
			return listOfTabs.length;
	}
	
	function changetab(id) {
		//set them all to be invisible
		listOfTabs = document.getElementById('picturesalbum').getElementsByTagName('div');
		
		for (x=0; x<listOfTabs.length; x++) {
			listOfTabs[x].style.display='none';
		}
		currentTab = id;
		
		document.getElementById('tab'+id).style.display='inline';
			document.getElementById('tab'+id).className='tab';
		checkLinks();
	}
	
	function nexttab() {
		if (currentTab<getNumberOfTabs()-1) {
			document.getElementById('tab'+currentTab).style.display='none';
			currentTab++;
			document.getElementById('tab'+currentTab).style.display='inline';
			document.getElementById('tab'+currentTab).className='tab';
			checkLinks();
		}
	}	
	
	function previoustab() {
		if (currentTab>0) {
			document.getElementById('tab'+currentTab).style.display='none';
			currentTab--;
			
			document.getElementById('tab'+currentTab).style.display='inline';
			document.getElementById('tab'+currentTab).className='tab';
			checkLinks();
		}
	}	
	
	function checkLinks() {
			if (currentTab<getNumberOfTabs()-1) {
				document.getElementById('nextlink').style.visibility = 'visible';
			}
			else {
				document.getElementById('nextlink').style.visibility = 'hidden';
			}
			
			if (currentTab>0) {
				document.getElementById('prevlink').style.visibility = 'visible';
			}
			else {
				document.getElementById('prevlink').style.visibility = 'hidden';
			}
	}
	// JavaScript Document