AJAX How to use key:value - php

Question

My form:
<form action="html_post.php" method="post" id="myform">
<textarea id="textarea" placeholder="Add your comment" name="posting"> </textarea>
<input class="button" type="button" name="send" value="Send">
</form>
I have such code
$(".button").click(function () {
var content = $("#myform").serialize();
$.ajax({
url: "add_post.php",
type: "POST",
data: {
text: content,
action: "add_post"
},
success: function () {
$('#comment_block').load('list_post.php');
document.getElementById('textarea').value = "";
}
})
});
And such php:
echo mysqli_error($connection);
if (strlen($_POST['posting']) >= 5) {
$text = htmlspecialchars($_POST['posting']);
$insert = "INSERT INTO post(content) VALUE ('$text')";
mysqli_query($connection, $insert);
}
But it does not add text to db. I'm just learning ajax and it's my first experience with key:value so can you help me?
And yep, there is no shown errors

Answer 1

The way you've written it, there is no $_POST['posting']. Instead, $_POST['text'] contains a URL-encoded string containing all the inputs in the form, i.e. a string like "posting=blah blah blah".
What you probably want is:
$(".button").click(function () {
var content = $("#myform").serialize();
$.ajax({
url: "add_post.php",
type: "POST",
data: content + '&action=add_post',
success: function () {
$('#comment_block').load('list_post.php');
document.getElementById('textarea').value = "";
}
})
});

Answer 2

Based on your posted code, on the server there will be two keys set in the $_POST variable. These are the ones that you define at your ajax request in javascript: text and action.
So while you check $_POST['posting'] it does not exists, but there are $_POST['text'] and $_POST['action']. $_POST['text'] will contain all the form fields as an URL-encoded string, like "posting=xyz". In order to access these values, you could use the parse_str() php function that parses this string as it were a query string.
So the condition at the server side could be something like as follows.
if (isset($_POST['text'])) {
// $formdata passed in by reference, it will contain all the form fields
parse_str($_POST['text'], $formdata);
}
if (isset($formdata['posting']) && strlen($formdata['posting']) >= 5) {
// Perform db operation
}