Inspect the database using JavaScript

Question

Inspect the database using JavaScript

I'm currently working on a project using JSP and Servlets. On one of the pages, there is a dropdown list and I need to check if the selected value is present in the database. Right now, it only checks when I click a button but I want it to check whenever the value in the dropdown list changes.

For example:

<select id="abc">
<option value="1">test1</option>
<option value="2">test2</option>
<option value="3">test3</option>
</select>

So far, I've used JavaScript like this:

<script> 
var e = document.getElementById("abc");
var str = e.options[e.selectedIndex].text;
</script>

Now, how can I check the value of 'str' in the database within JSP?

I believe it can be done with JavaScript, but I'm not certain. Also, I'm unsure how to check the database value in a script tag. It may involve AJAX as well. Please provide some guidance.

javascript ajax database jsp

Answer 1

Answer №1

Looking for a solution that involves AJAX and PHP? Here's one:

To start, make a POST request to your backend server with the necessary data:

jQuery.ajax({
    type: "POST",
    url: "http://www.yourbackend.php",
    data: {
             username: username,
             password: password
    },
    success: function(data){}
});

Next, check if the value exists in your backend script. For instance, if you're working with PHP using PDO, the code might resemble this:

$query = $db->prepare('SELECT * FROM users WHERE username = :name');
$query->bindParam(':name', $_POST['username']);
$query->execute();
echo json_encode(array('exists' => $query->rowCount() > 0));

(In this scenario, the username is being queried).

The result of whether the value exists or not will be returned in JavaScript's data, giving you the flexibility to handle it according to your needs.

Give it a try and let me know how it goes!

Answer 2

Looking for a solution that involves AJAX and PHP? Here's one:

To start, make a POST request to your backend server with the necessary data:

jQuery.ajax({
    type: "POST",
    url: "http://www.yourbackend.php",
    data: {
             username: username,
             password: password
    },
    success: function(data){}
});

Next, check if the value exists in your backend script. For instance, if you're working with PHP using PDO, the code might resemble this:

$query = $db->prepare('SELECT * FROM users WHERE username = :name');
$query->bindParam(':name', $_POST['username']);
$query->execute();
echo json_encode(array('exists' => $query->rowCount() > 0));

(In this scenario, the username is being queried).

The result of whether the value exists or not will be returned in JavaScript's data, giving you the flexibility to handle it according to your needs.

Give it a try and let me know how it goes!

Inspect the database using JavaScript

Answer №1

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