function check_number(id, hideelement) {
	number=document.getElementById(id).value;
	number=number.replace(",","");
	number=number.replace(".","");
	var anum=/^\s*\d+[ 0-9]*$/
		if(!anum.test(number)) {
			
			document.getElementById(id).focus(); 
			
			document.getElementById(id).style.background='red';
			document.getElementById(hideelement).style.display='none';
			alert('Nespravne zadane mnozstvo');
		} else {
			document.getElementById(hideelement).style.display='';
		}
}