function hide_show_divs(num){
		if(document.getElementById('center_disable_'+num).style.height=='0px') {
			document.getElementById('center_disable_'+num).style.height='auto';
			document.getElementById('center_disable_'+num).style.overflow='visible';	
			document.getElementById('hide_show_arrow_'+num).src='images/layout/button_up.jpg';	
		}
		else {
			document.getElementById('center_disable_'+num).style.height='0px';
			document.getElementById('center_disable_'+num).style.overflow='hidden';
			document.getElementById('hide_show_arrow_'+num).src='images/layout/button_down.jpg';	
		}
}