codice:
<script language="javascript" type="text/javascript">
 /* verifica la correttezza della mail inserita */
 /* prelevato qui http://www.javascriptkit.com/script...t2/acheck.shtml */
 
var testresults
 function checkemail(){
 var str=document.validation.emailcheck.value
 var filter=/^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i
 if (filter.test(str))
 testresults=true;
document.getElementById('boxMail').innerHTML='[img]mailOK.jpg[/img]' 
 else{
 alert("Prego, inserisci un indirizzo email valido!\n\nEs. mionome@free.it")
 testresults=false
 }
 return (testresults)
 }
 </script>
 


<form name="validation" onsubmit="return checkbae()">
 Prego, inserisci una e-mail valida  <input type="text" size="18" name="emailcheck" /> <span id="boxMail"></span> 
<input type="submit" value="Submit" />
 </form>