Pass data from JQuery to database via Javascript/AJAX/JSON/PHP - php

Question

I am attempting to add data to my database from my HTML code via the use of JQuery, AJAX/JSON and PHP using an MVC model. Below is a small sample of what I am looking to achieve.
In my front end I have a checkbox with different options and a button named 'Add'. The selected elements from here are picked up by a Javascript function, which I have tested properly, once this is done I call another Javascript function to do the AJAX/JSON . What I am still fresh on is the actual AJAX/JSON process that sends the data to PHP.
My Javascript function:
function add_fruits(fruit_name, fruit_type){
var success = "Fruit added";
var error = "Fruit not added";
var params = {
'fruit_name' : fruit_name,
'fruit_type' : fruit_type
};
$.ajax({
type: "POST",
url: "add_fruits.php",
async: false,
data: params,
success: function(success){
alert(success);
},
error: function(error){
alert(error);
}
});
}
My PHP function:
<?php
header("Access-Control-Allow-Origin: *");
header('Content-type: application/json');
require_once 'lib/connection_files.php';
if($_SERVER['REQUEST_METHOD'] =='POST')
{
$fruit_name = no_sql_injection($_POST['fruit_name']);
$fruit_type = no_sql_injection($_POST['fruit_type']);
$fruits = new fruits();
$result = $fruits->add_fruits($fruit_name, $fruit_type);
$tmp = mysql_num_rows($result);
if($result == 1)
{//RESULT must return 1 to verify successful insertion to database
//send confirmation to front end
}
else
{
//send error message to front end
}
}
else{
//tell front end there was error sending data via AJAX
}
?>
Note that the add_fruits() function takes care of doing the Queries to the database, I did not include it here because it is irrelevant to my issue.

Answer 1

Just do echo in your PHP:
PHP
else {
//send error message to front end
echo "Error Adding Fruits";
}
JS
success: function(data) {
if (data == "1") {
//data added to db
}
else {
alert(data);
}
}