JavaScript Validation

[sysout]

Js :

<script type="text/javascript" language="javascript">
success = false;
function notNull(id, requirement, errornya){
	inputId = document.getElementById(id).value;
	err = document.getElementById(errornya);
	if (inputId == ""){
		err.innerHTML = "* "+requirement + " must be filled";	
		success = false;
	}	
	else{
		err.innerHTML = "";		
		success = true;
	}
}
function mustNumber(id, requirement, errornya){
	inputId = document.getElementById(id).value;
	err = document.getElementById(errornya);
	if (isNaN(inputId) == true){
		err.innerHTML = "* "+requirement + " must be a number";	
		success = false;
	}	
	else{
		err.innerHTML = "";		
		success = true;
	}
}
function atLast(form){
	if(success == false){
		alert("Sorry, still error");
		form.gatewayId.focus();
		return false;
	}
}
</script>

the Form :

<form id="form" action="insertGateway.php" method="post" onsubmit="return atLast(this)">
Gateway Id : <input name="gatewayId" id="gatewayId" type="text" onBlur="notNull('gatewayId', 'Gateway Id', 'errorGateway')" /> <span class="ErrorCss" id="errorGateway"></span><br/>
Com Port : <input name="comPort" id="comPort" type="text" onBlur="notNull('comPort', 'Com Port', 'errorComPort')" /> <span class="ErrorCss" id="errorComPort"></span><br/>
Baud Rate : <input name="baudRate" id="baudRate" type="text"  onBlur="notNull('baudRate', 'Baud Rate', 'errorBaudRate'); mustNumber('baudRate', 'Baud Rate', 'errorBaudRate')" /> <span class="ErrorCss" id="errorBaudRate"></span><br/>
</form>

still gives me error..
why it don't want to focus?
the baud rate validation is error too..oh god..fixed it all night, but still errors..
please help me.

thanks