如何在ajax中发送特殊字符作为值并在php端解码？

I have the code ,

$.ajax({
        type: "POST",
        url: "my_ajax.php",         
        dataType: 'json',
        data: ({ description : description.val(), project_id : project_id.val()}), 
        success: ( $(".succes_update_description").append("Update Successfull") )
        });

php side I have

<?php mysqli_query($conn, "update someDB.someTable set description='".$_POST['description']."' where id='".$_POST['project_id']."'"); ?>

after that when I try to

so , when description.val() contains characters like ' or " or \ , I can't update the string in mysql. how can I resolve that?

Don't trust your user, never! Escape or cast all the values you're using in your queries. Your code should look something like this:

$description = mysqli_real_escape_string($_POST['description']);
$id = (int)$_POST['project_id'];

mysqli_query($conn, "UPDATE someDB.`someTable` SET `description`='".description."' WHERE `id`='".$id."'");