how to pass js variable to php via ajax

Question

Hello I am new to js and I stuck on the problem about passing variables to php via ajax.

 <script>
            $date = "123";
            $.ajax({
                url: './record.php', 
                type: "POST",
                dataType:'text', 
                data: ({'date': date}),
                success: function(data){
                    console.log("successfully");
                }
            }); 
</script>

And below is my code in record.php file.

<?php
session_start();
if(!empty($_POST['date'])){
    //$hello = 'hh';
    $_SESSION['date'] = $_POST['date'];
    echo($_SESSION['date']);
}else{
    echo "its empty(var)";
}

?>

Page always print out "its empty(var)" and I checked console, it shows "successfully"... I already stayed on this problem for several hours and looked for a lot of similar post, but I still can't find where is the problem. Can anyone have a look at it? I also already loaded the jQuery library.

Answer 1

you ar mixing js variable with php variable, js variables are declared with var and php variables are declared with $fieldname

<script>
            var date = "123";
            $.ajax({
                url: './record.php', 
                type: "POST",
                dataType:'text', 
                data: {'date': date},
                success: function(data){
                    console.log("successfully");
                }
            }); 
</script>

Answer 2

if you want a PHP variable insite javascript you should define php variable first then asign it into js.

<?php $date = "123"; ?>';

<script>

            var date=<?php echo $date; ?>';
            $.ajax({
                url: './record.php', 
                type: "POST",
                dataType:'text', 
                data: ({'date': date}),
                success: function(data){
                    console.log("successfully");
                }
            }); 
</script>

Hope it wil helps you.

Answer 3

You cant mix server (php) and client (js)

you might to this

<?php $var = 0?>

then in html you create

<input id="something" type="hidden" value="<?php echo $var?>">

then you get that value via

document.getElementById("something").value;

Answer 4

You are declaring $date and pass in your ajax as date.

Try this:

<script>
        var date = "123";
        $.ajax({
            url: './record.php', 
            type: "POST",
            dataType:'text', 
            data: {'date': date},
            success: function(data){
                console.log("successfully");
            }
        }); 
</script>