function hide(divId) {
			if (document.layers) {
				document.layers[divId].visibility = 'hide';
				document.layers[divId].display = 'none';
			}else if (document.all) {
				document.all[divId].style.visibility = 'hidden';
				document.all[divId].style.display = 'none';
			}else if (document.getElementById) {
				document.getElementById(divId).style.visibility = 'hidden';
				document.getElementById(divId).style.display = 'none';
			}
		}
			
		function show(divId) {
			hideAll();
			if (document.layers){
				document.layers[divId].visibility = 'show';
				document.layers[divId].display = 'block';
			}else if (document.all) {
				document.all[divId].style.visibility = 'visible';
				document.all[divId].style.display = 'block';
			}else if (document.getElementById) {
				document.getElementById(divId).style.visibility = 'visible';
				document.getElementById(divId).style.display = 'block';
			}
		}
		
		function hideAll(){
			hide('a');		
			hide('b');
			hide('c');
		}