function IsAlnum( id ){
	var res = "";
	val = document.getElementById(id).value;
	for (var i=0; i<val.length ; i++ ) {
		if (val.charAt(i)<" " || val.charAt(i)> "~" ) {
		} else {
			res += val.charAt(i);
		}
	}
	document.getElementById(id).value = res;
}