io ho fatto così ma non funziona:

codice:
<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	<title>Web Utilities Kekko</title>
	
	
	<link rel="stylesheet" type="text/css" href="homePage.css" />
	
	
	<script type="text/javascript" >
		
				
		
		function checkemail()
		{
			
			var mail = document.getElementById('Temail');			
			
			if(mail == 'dd')
			{
				alert(mail);
				return true;
			}else
			return false;
			
			
		}
			
		
	</script>

	<!--
	<style type="text/css">		

		@import url(homePage.css);	
							
		form {
			
			width: 20em;
			
		     }
		 
		fieldset{
		
			background-color: red;
				   
				  }	 
		 		
	</style>
		-->
</head>
<body>
	<div id="general">
		<div id="top">
			[img]webUtilities.gif[/img]
					
				<form id="utenteRegistrato" method="post" action="testdb.php" onsubmit="return checkemail()">
					<fieldset >
						<legend>Accesso Utenti</legend>
							
						<label>Email:</label>
						<input type="text" name="utemail" id="Temail"></input>
						

								
						<label>Password:</label>
						<input type="password"></input>
						
		
						<button type="submit" value="invia" onclick="checkemail()">Invia </button>						
						

						
					<label>Se non sei registrato clicca Qui</label>						
				</fieldset>				
			</form>						
		</div>
		<div id="barra">
			<table>
				<tr>
					<td>HOMEPAGE </td>					
					<td>REGISTRAZIONE</td>
					<td>RUBRICA  </td>
					<td>AGENDA </td>										
					<td>CALCOLATRICE </td>					
					<td>SVEGLIA  </td>					
					<td>CONTATTI </td>	
				</tr>
			</table>
		</div>
	</div>
</body>
</html>