function change_div() {		
		curr_div=document.getElementById('div_no').value;
		if (curr_div < 3) {
			next_div=parseInt(curr_div)+1;
		}
		else {
			next_div=1
		}

		document.getElementById('div_'+curr_div).style.visibility='hidden';
		document.getElementById('div_'+curr_div).style.display='none';	
		
		document.getElementById('div_'+next_div).style.visibility='visible';
		document.getElementById('div_'+next_div).style.display='block';	
		document.getElementById('div_no').value=next_div;
		setTimeout('change_div()', 5000);
}