Fijate si te sirve:
Código PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>test</title>
<script>
function valida(obj,obj2){
ok=false;
for(i in obj2){
if(obj2[i]==obj.value){ok=true;break;}
}
if(!ok){alert('valor incorrecto');obj.value='';}
}
</script>
</head>
<body><form name="form1" method="post" action="">
<input name="caja1" type="text" id="caja1" onBlur="valida(this,[3,7,10])" >
<input type="submit" name="Submit" value="Enviar">
</form>
</body>
</html>