Passing variable javascript to PHP using AJAX

Question

I am trying to pass a single variable from javascript to PHP using jQuery AJAX.

Javascript:

$(document).ready(function() {
    $('.ok').on('click', function(e){

        var value = 5;

        $.ajax({
            url: 'tabulka.php',
            type: "POST",
            data: {x : value},
            success: function(){
                alert(value);
            }
        });
    });
});

PHP:

if($_SERVER['REQUEST_METHOD']){
    $value = $_POST['x'];
    echo $value;
}

I get the alert from ajax with the expected value but in PHP I get this error: Notice: Undefined index: value in C:\\xampp\\htdocs\\test\\tabulka.php on line 71 When I uncomment the dataType: 'json' I don't even get the alert from AJAX.

Answer 1

Instead of this

data: ({value : value}),

Try using this,

 data: "value="+value,

And you are not at all passing "OK" but you are receiving it. If you want to pass OK also as a parameter try this.

data: "value="+value+"&OK=Somevalue",

That should work.

Answer 2

Your JavaScript

data: {'value' : value}

notice the single quote and no parenthesis

Your PHP:

If(isset($_POST['value'])){
   $val = $_POST['value'];
}

Your JavaScript was formatted incorrectly. data is an object, or an associative array in other words.

Your PHP code has unnecessary string comparison. Whenever a post is made to a PHP script, you will access them using $_POST array.

For instance, if you posted this via AJAX

data:{ 'name' : 'jake', 'age' : 1024}

You would access them in PHP by

  $name = $_POST['name']
    $age = $_POST['age']

Also, it is wise to use PHP isset to verify that a post variable exists before trying to access them. That way you will not have an exception if expected post data is not.

Answer 3

check following line

var value = $(this).find('td:first').html();

set some hard coded value for 'value' variable like below

var value='some value';

if above works then check the value you assigned using $(this).find('td:first').html()