Gracias JavierB.
aqui tienes el codigo entero, he probado pero ahora solo funciona con el pass1 y si te equivocas no sale error, simplemente no hace nada.
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css">
<!--
-->
</style>
<script language="JavaScript">
<!--
function password() {
var testV = 1;
var pass1 = prompt('Estimate Agency , enter the password that provides you. Thank You','');
while (testV < 3) {
if (!pass1)
if (!pass2)
if (!pass3)
history.go(-1);
if (pass1 == "ES589221" || pass2 == "es21" || pass3 == "es22") {
alert('Welcome, you can view the booking now');
window.open('booking.htm');
break;
}
testV+=1;
var pass1 =
prompt('Denied Access - Wrong Password, Try again please.','Password');
}
if (pass1!="ES589221" || pass2!="es21" || pass3!="es22" & testV ==3)
history.go(-1);
return " ";
}
</script>
</head>
<table width="500" border="0">
<tr>
<td><div align="center">
<input type="button" value="Access to Booking system" onClick="password()" name="button">
</div></td>
</tr>
</table>
</body>
</html>