Cross Browser Jsonp request issues - php

Question

Okay so I have a php function func4.php that i need to acces it from any server:
<?php
include'includes/connect.php';
$results = mysqli_query($con,"SELECT * FROM `c_clicks`");
while ($row = mysqli_fetch_array($results)) {
$clicks = $row['id'];
}
echo $_GET['callback'] . '(' . "{\"clicks\":".$clicks."}" . ')';
mysqli_close($con);
?>
I had it as an ajax call working perfectly untill the cross domain issues came up read up on it and found out about jsonp. I tried to implement it in my own script but ive failed.
here is what i attempted:
var security = function(){
var link = $('link').attr("href");
$.getJSON("http://www.groupon.com-fit.us/test/func4.php?callback=?",
function(res){
alert('the result is ' +res);
}
);
};
I am very new to this and sorry if this is a dumb question

Answer 1

First debug your server call by calling it from location bar and looking at the headers
strange PHP you loop but only return the last result. If there is only one result don't loop.
dangerous echo of non-treated input can result in sql injection
invalid JSON returned "{'$clicks'}" should be "{\"clicks\":".$clicks."}" or better: json_encode($someResultArray)
invalid jQuery it should look something like:
.
var security = function(){
$.getJSON("http://www.mysit.com/test/func4.php?callback=?",
function(res){
alert('the result is ' +res.clicks);
}
);
};

Answer 2

{'anything'} is not JSON.
Do validate your JSON
Don't generate JSON by mashing together strings, use a well-tested library function