Hola, txarly.
A ver si esto te vale:
Código PHP:
<html>
<head>
<script>
function validar(e) {
tecla = (document.all)?e.keyCode:e.which;
if(tecla==86 && e.ctrlKey)
return false;
}
</script>
</head>
<body>
<input type="password" name="textfield" onKeyDown="return validar(event)">
</body>
</html>
Saludos,
