How to get data back from a $.post call? - ajax

Question

I don't want to refresh a page when I am searching through a database eg. on post, so I had help in using a $.post call which works for sending information. There is a .done(function( data ){ line which I haven't used yet.
I also came across this question which I'm not sure if this ties to my question.
Return $.get data in a function using jQuery
I'm trying to search through a database, string match, and return the rows with matching strings. But I want to do this without refreshing the page so I would think that I am using the $.post call and using the .done(function( data ){ which is triggered by javascript (a button).
So I have two parts, the page I'm on and a separate PHP page that processes the call when made.
How do I make the bridge where I can return the data back? Or is there an easier way to do this?

Answer 1

The method .done(function(){}) is exactly what You would like to use, but You can also take a look at third argument (callback) of $.post function.
On server side, do all the queries and prepare the stuff in jsoned array like:
// set up data to send
$contentArray = [
'content' => 'Some content',
'foo' => 'bar',
];
$jsonResults = json_encode($contentArray);
// you can always send header('Content-Type: application/json'); instead of using simple die function.
die($jsonResults);
Then on client side:
<div class="content-container"></div>
<script type="text/javascript">
function someFunc() {
(...)
$.post(addr, values, function(res) {
var response = $.parseJSON(res);
$('.content-container').html(response.content);
});
}
</script>
This should update the content of the .content-container class only. You can send as much as you want, even prepared view to be displayed in the container. This is up to You.
EDIT:
Just to be sure, you're calling someFunc() on some button click event, right? If not, do it as follows:
<div class="content-container"></div>
Click here
<script type="text/javascript">
function changePageContent(addr, contentId) {
$.post(addr, {contentId:contentId}, function(res) {
var response = $.parseJSON(res);
$('.content-container').html(response.content);
});
}
$('.callMe').on('click', function() {
changePageContent($(this).attr('href'), $(this).attr('data-content-id'));
return false;
});
</script>
someScript.php:
<?php
// you should force your script to allow only XML HTTP request here
if(empty($_SERVER['HTTP_X_REQUESTED_WITH']) || strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) != 'xmlhttprequest') {
die('AJAX requests only..');
}
// always remember to escape somehow your post values before you use them
$contentId = is_numeric($_POST['contentId']) ? intval($_POST['contentId']) : null;
if (null == $contentId) (...) // throw exception or return status=false
// do your mysql query like: "SELECT * FROM content WHERE id=".$contentId;
// well, it would be better to send headers instead of that
die(json_encode([
'status' => true, // this is a good practice to send some info, if everything is fine, if mysql row has been found etc..
'result' => $result, // mysql row, this is just in case you need other values to display
'content' => $result['content'], // I assume you have 'content' column in your mysql
]));
?>

Answer 2

Take a look at the docs for Ajax, there really is a lot of info there which will help.
In short, you could do something like this:
function myPost() {
// Set the data
var data = {
'key' : 'value',
'key_2' : 'value_2'
};
// Do the post
$.post( '/your-url/', data, callBack );
}
function callBack( data ) {
// If the $.post was successful
success: function( data ) {
// do stuff
console.log( data ); // returned from your endpoint
},
// If there was an error
error: function( jqXHR, textStatus ) {
// do stuff
console.log( "Request failed: " + textStatus );
}
}
// On click of your element, fire the post request
$('#element').on('click', function() {
myPost();
});