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Jquery ajax – How can I retrieve data from a database using AJAX and save the results in a variable?

I’m new to jQuery and AJAX and I’m working on a login-page as a project and I need to retrieve data from a database using AJAX. I’m not 100% fluent in English so I’ll do my best to explain the problem (with help from Google Translate).
Here’s the code I’m using:

index.html

<!DOCTYPE html>
<html>
  <head>
  <title>Login</title>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.0/jquery.min.js"></script>
  </head>
  <body>
    <form validate="">
      <input type="text" placeholder="Username" id="username" required/><br />
      <input type="password" placeholder="Password" id="password" required/><br />
      <input type="submit" id="submit" value="Login" />
    </form>
    <script type="text/javascript">
    // when document is loaded
    $(document).ready (
      // when submit is clicked
      $("#submit").click (
        // sets test to null
        var test = null;
        // sets username to value of username input
        var username = document.getElementById("username").value;
        // AJAX request 
        $.ajax({
          type: "POST",
          async: true,
          url: test.php,
          data: {username: username},
          success: function (data) {
            test = data;
            console.log(test);
            return test;
          }
        });
      );
    );
    </script>
  </body>
</html>

test.php

<?php
// connects to database
$conn = mysqli_connect('server', 'username', 'password', 'database');

// sets var username to POST username value
$username = $_POST['username'];

// SQL Query
$sql = "SELECT * FROM users WHERE username='" . $username . "'";
$result = mysqli_query($conn, $sql);

// sets result to mysqli_fetch_assoc()
$result = mysqli_fetch_assoc( $result );

// echos $result
echo $result['password'];

// closes database connection
mysqli_close( $conn );
?>

Console Log

Console Output:
“`
[DOM] Input elements should have autocomplete attributes (suggested: “current-password”): (More info: https://www.googlesite.com)
​

Uncaught SyntaxError: Unexpected token var ajax.html:19

I've looked at the code and I can't seem to find an error.
Thanks in advance! ;)

>P.S.
>It's probably going to end up being some stupid typo.
>Other than that, have a great day!
Tags:

2

Answers


  1. 0

    You need to pass in a function to your document.ready() call and your click() call. 

         <script type="text/javascript">

        $(document).ready(function() {
            Your variables here...

            $('#submit').click(function() {
                ... Ajax call here.
            });
        });
    </script>
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  2. 0

    Instead of using click event you can use submit.

    In your case, just give id to your form like –

    <form validate="" id="submit">

    Now,
    In your js script – 

    $(function() { //shorthand document.ready function
    $('#submit').on('submit', function(e) { 
        e.preventDefault();  //prevent form from submitting
        console.log(data);
        $.ajax({
          type: "POST",
          async: true,
          url: test.php,
          data: $(this).serializeArray(),
          success: function (data) {
            console.log(data);
          }
        });
    });
});

    So check your whole code – 

    <!DOCTYPE html>
<html>
  <head>
  <title>Login</title>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.0/jquery.min.js"></script>
  </head>
  <body>
    <form validate="" id="submit">
      <input type="text" placeholder="Username" id="username" required/><br />
      <input type="password" placeholder="Password" id="password" required/><br />
      <input type="submit" value="Login" />
    </form>
    <script type="text/javascript">
    // when document is loaded
    $(function() { //shorthand document.ready function
    $('#submit').on('submit', function(e) { 
        e.preventDefault();  //prevent form from submitting
        console.log(data);
        $.ajax({
          type: "POST",
          async: true,
          url: test.php,
          data: $(this).serializeArray(),
          success: function (data) {
            console.log(data);
          }
         });
        });
     });
    </script>
  </body>
</html>

    Hope this will help you.

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