OnClick Function Get Next Record PHP AJAX MYSQL - php

Question

I am getting stuck with an example I found on SO about this very topic.
See original article: How do I show next result in MySQL on "onclick" in JavaScript?
I followed this example to the T, with the exception of using some updated functions. Anyway, I am getting stuck on one step, was hoping someone could explain.
within the jquery below, the code is setting $number and then passing number in the POST action to the php file. My problem is is that when echo 'count', it echos "$number". I am not sure why it is not passing an actual number such as "0" rather than the string "$number". I am probably doing something seriously wrong, but not sure what is going on.
jquery
$(function(){
$('#showMore').click(function(event) {
event.preventDefault();
$number = $('.result').size();
$.ajax({
type: "POST",
url: "getNext.php",
data: "count=$number",
success: function(results){
$('#results').append(results);
}
});
});
PHP
I am passing count into a variable so that I can use it in a query, like so:
$pst = $_POST['count'];
SQL
$sql = "SELECT * FROM tablename LIMIT $pst,1";
I went ahead and captured the error I am receiving (see below) - as mentioned previously it is inserting "$number" instead of an actual number.
"Fatal error: Query Failed! SQL: SELECT * FROM tablename LIMIT $number,1
any help would be much appreciated

Answer 1

Try changing this line:
data: "count=$number",
To this
data: "count=" + $number,
Javascript doesn't "read" strings for variables like php does, so you need to concat the value manually.

Answer 2

problem is you are sending count as string which is $number in your case.
your data should be
data: {"count":$number}, //notice `"`
send it as object.
or
$data:"count=" + $number,
concate the var
i prefer data as object which is more readable.