function display_div(divnm){
	 document.getElementById(divnm).style.visibility = "visible";
}

function display_div_sub(divnm,mdivnm){
	 document.getElementById(mdivnm).style.visibility = "visible";
	 document.getElementById(divnm).style.visibility = "visible";
}

function hidden_div_single(divnm){
	 document.getElementById(divnm).style.visibility = "hidden";
}
function hidden_div(){
	 document.getElementById("drop1").style.visibility = "hidden";
	 document.getElementById("drop2").style.visibility = "hidden";
	 document.getElementById("drop3").style.visibility = "hidden";
	 document.getElementById("drop4").style.visibility = "hidden";
	 	 
}