var subsOn = false;
function showSubs() {
	                 subsOn = !subsOn;
				  	 for (var i = 1; i<=20; i++) {
				  	   if (document.getElementById("sub"+i)) {
						   if(subsOn){
						      document.getElementById("sub"+i).style.display="block";
						   }
						   else{
							  document.getElementById("sub"+i).style.display="none";
						   }
					   }
				  	 }
}