// JavaScript Document
function checkNumber(obj) {
	if(isNaN(obj.value)) {
		obj.value=0;
		obj.select();
	}		
}
function showhidelayer(layer) {
	var div = document.getElementById(layer);
	div.style.display = div.style.display=='none'?'block':'none';
	div.style.visibility = div.style.visibility=='hidden'?'visible':'hidden';
	
}