function createUser() {
	var error = false;
	for (field_id in required_fields) {
		if (!required_fields[field_id]['param'].test(document.getElementById(field_id).value)) {
			error = true;
			alert(required_fields[field_id]['error']);
			document.getElementById(field_id).className = 'create_user_textfield textfield_singleline_error';
			document.getElementById(field_id).onkeyup = function () {
				this.className = 'create_user_textfield textfield_singleline';
				this.onkeyup = null;
			}
			
			document.getElementById(field_id).focus();
			break;
		}
	}
	
	if (!error) {
		document.forms['create_user_form'].submit();
	}
}