function manage(dv_name)
{
	var total_div = new Array('div_1','div_2','div_3','div_4');
	
	for (i=0; i<total_div.length; i++)
	{
		if (dv_name==total_div[i])
		{
			if (document.getElementById(total_div[i]).style.display == 'none') {
				document.getElementById(total_div[i]).style.display = 'block';
			}
			else if (document.getElementById(total_div[i]).style.display == 'block') {
				document.getElementById(total_div[i]).style.display = 'none';
			}
		}
	}
}