Ajax getting response undefined and Uncaught ReferenceError - php

Question

Code:
query = "http://localhost:8080/working_login.php?name=" + name + "&password=" + pass;
console.log(query);
$.ajax({
type: "GET",
url: query,
dataType: "script",
success: function(data){
console.log(data);
console.log("success");
},
error:function (msg) {
console.log("error on page");
}
});
I am getting undefined in data and as I am returning 'valid_user' from the server side made in php, getting error.
Uncaught ReferenceError: valid_user is not defined
(anonymous function)
Php server side code:
$sql = "SELECT id FROM users WHERE name ='$name' AND password = '$password';";
$result = mysql_query($sql) or die('Can not Register user' . $sql );
$rows = mysql_num_rows($result);
if($rows > 0)
{
echo("valid_user");
exit();
}
else
{exit("not valid user");}

Answer 1

when using the script dataType in the jquery ajax reqeust, the returned result is interpreted as javascript code, but you return plain text
simply change dataType: "script" to dataType: "text".

Answer 2

You probably didn't mean to tell jQuery that you were expecting a script in return. What's being returned isn't a properly formatted script, so it's giving you an error when the browser parses as a script.
You could just do the following:
$.get("http://localhost:8080/working_login.php?name=" + name + "&password=" + pass, function(data) {
if(data == 'success')
{
alert("Success");
}
else
{
alert("Failed");
}
});