I have 3 fields: contract number, start date and end date.
How do I validate two fields simultaneously? That is, the start date and end date must be fulfilled. If they are not, I have to send only ONE message (not two, as I am used to - one for each field).
To submit this form, it is enough that either the contract number or the dates are fulfilled. There is no need to fill in both.
I think you solve this way with cascading ifs:
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Untitled Document</title>
<script language="javascript" type="text/javascript">
function emitir(){
var numero = document.forms["formEmitir"].numero.value;
var dataini = document.forms["formEmitir"].dataini.value;
var datafim = document.forms["formEmitir"].datafim.value;
if(!numero && !dataini && !datafim){
alert("Preencha com o número do contrato ou as datas!");
} else {
if(numero && (dataini || datafim)){
alert("Preencha apenas o número OU as datas!");
} else if(numero) {
alert("Será emitido através do número do contrato...");
} else if(dataini && datafim){
alert("Será emitido através das datas...");
} else {
alert("Preencha ambas as datas de início e fim!");
}
}
}
</script>
</head>
<body>
<form name="formEmitir">
<fieldset>
<legend>Seu Contrato</legend>
<p>Pelo número: <input type="text" name="numero" /></p>
<p>Pela data: de <input type="text" name="dataini" /> a <input type="text" name="datafim" /></p>
<p><button onclick="emitir();">Emitir</button></p>
</fieldset>
</form>
</body>
</html>