Develop Reference

How do I transfer the PHP variables to another javascript file?

So my goal is to use PHP to get data from a PostGreSQL database. I want to use this data in a separate javascript file so I can display it on the screen a certain way that I have my website configured. All the tutorials that I have seen online just puts a script tag inside the PHP file but I cannot do that because my website display javascript code is in the separate file. I just need the numbers to be in the javascript file that I got from the PHP file that got its data from the PostGreSQL database. How can I do this?
I just need help with the means to get to the ends because I have researched on my own but it is always not exactly what I want.
PHP:
<?php
$myPDO = new PDO('pgsql:host=myHost; dbname=myDBName', 'myUsername', 'myPassword');
?>
$result = $myPDO->query("SELECT * FROM table WHERE id = 'someID'");
Now I want to use this row's values in another javascript file. How can I do this?

You could use Ajax for this.
You could so something like this in your JS file:
$.ajax({
type: "GET",
url: 'FILENAME.php',
success: function(data){
alert(data);
}
});
and then in your FILENAME.PHP just return the values.
Your JS should then pull through whatever has been returned, in this case, your database query.

Your JS file needs to request the data from your PHP controller, via an AJAX request. You can then manipulate the returned data object whichever way you like.

We have mainly two methods to pass php value to javascript variable
Simple variable method at the time of first page load
<script>
var js_variable = <?php echo $data_php_variable; ?> ;
//this is working only at the first time of the page load
//you can also parse the data to any format
</script>
Use AJAX call to trigger a PHP request and manipulate return PHP value in JS
$.ajax({
type: "GET", //get or post method
url: 'FILENAME.php', //php request url
data :{}, //optional ,you can send data with request
success: function(res){
// this 'res' variable is the php return data in the form of js data
console.log(res);
}
});
ajax method is more dynamic ,it can use any time request handling

use the javascript ajax to call a php api
pass your data at php in your view file , use something like:
var phpData = JSON.parse("<?php echo json_encode($data)); ?>");

How to pass resource from php to javascript

So I have three different separate files:
functions.php (all functions for the database)
main.html (my main program)
main.js (all javascript functions)
Now, I want to call a function in PHP through AJAX. To do that, I need to pass $conn.
$conn = sqlsrv_connect($serverName, $connectionInfo);
It's a resource, so I can't use json_encode.
The way I set the everything up now is that the php-file is required in the html so I can use the functions and when I change the
value of a dropdown, the js is called.
How can I pass the $conn variable to Javascript?
Regards

It doesn't work like that.
You should never be directly making calls to the database from the front-end.
Think of it as three separate levels. Your HTML/JS is the front-end, your PHP is your server, and your Database is on its own level.
So when the user does something on the front-end, say changes the value of a field and you want to update that in the database the following actions should happen:
Event triggers on JS
AJAX is called as a result of the event being triggered
PHP server receives the AJAX request and executes code to modify database
(optional) PHP server sends something back to the front-end to tell it that the request was successful
Read up on the concept of MVC: https://developer.mozilla.org/en-US/docs/Web/Apps/Fundamentals/Modern_web_app_architecture/MVC_architecture

Try this in php code as I assume functions.php
$conn = sqlsrv_connect($serverName, $connectionInfo);
echo $conn;//Don't try echo anything other
In Javascript
$.ajax({
type: "POST",
url: "functions.php",
success: function(data)
{
var conn = data; // here is your conn which comes from php file
}
});

First of all include jquery latest version from cdn
Create an API Url, and use POST method
site.com/api/insert.php // to insert into table
Use $.post() api of jquery to send data
var url = ""; // enter your URL HERE
var postData = {}; // object of post data with table name, cols and values
$.post(url, postData, function(data, status) {
// do what ever you want with data
})
ps: you can also create diff insertion / selection / update / delete api for different table. (recommended)
Read more about $.post() here

Do Ajax calls and maintain class structure

Hello I am wondering what is the common method of structuring ajax and php?
I am doing a website/application which have a lot of ajax calls. Also I do have a class in php I use for my main php code for keeping track of the user.
When I do ajax calls with jquery to smaller php files I need to re-declare my object I have in other files. I want the object that I have in my "main" php file. What is a good method to get the same object? Right now I am using jquery to pass the values from a div element (which comes from the object previously).
I feel this is not the best practice. I want to do it structured.
Example: I store the user session in User.
I have a button a user can click to get some information about his data. For this I have a jquery ajax call which sends and retrieves data for display. In that php file I do have to redo everything again, even if I include the class file, because the object is declared elsewhere.
Example. User can create lists in this kind of way.
I have the main index file which includes this file of new User. This type of stuff.
$user = new User();
if($_SESSION["user_connected"])
{
$user_profile = $twitter->getUserProfile();
$displayname = $user_profile->displayName;
}
$user->username = $displayname;
// Also user has an array of lists
jQuery
$('#createlistform').submit(function(event)
{
var newlistname = $('#listname').val();
var createlistRequest = $.ajax(
{
url: "ajax/ajax_add_list.php",
dataType: "html",
type: "POST",
data: {
listname: newlistname
}
}
);
the ajax_add_list file ajax is calling below. Now what I do to get this work is sending the username through as a data parameter to the php file from picking it up by $('#username').text() then set a new user with that username. It is not in the example now... but you get the point I think.
include_once("../user.class.php");
$theUser = new User();
if(class_exists('User'))
{
echo "yes class exists";
$newlistname = $_POST['listname'];
$theUser->createList($newlistname);
}
I wish I could get the same User object that was defined in my index file. I don't wanna create a new one. Although if this is how people do it when they have ajax I'll do it. I just want to know how you usually go by when dealing with different files here and there with javascript getting data from various places, while still maintaining a good structure with class and object.

Javascript array conversion to jQuery.post's data

I am trying to send different values to php script using jQuery.post
The data I want to send are links like this
http://example.com/image1.jpg
http://example.com/image2.jpg
http://example.com/image3.jpg
http://example.com/image4.jpg
I don't have an exact amount of these links they would vary depending on the user interacting with my script
I am storing these links in a javascript array "fileLinks".
what I want to do is to send these links to php using jQuery.post
Can I format these links in this shape?
jQuery.post(MyAjax.ajaxurl,
{ action : 'ajax-rform',
link1: http://example.com/image1.jpg,
link2: http://example.com/image2.jpg,
link3: http://example.com/image3.jpg,
link4: http://example.com/image4.jpg,
},
function(data){
jQuery("#fileupload").after('<h1>Success</h1><p>Your registration has been recieved.</p>');
}
);
In php I just need to use for loop and replace the link1 and http://example.com/image1.jpg with the arrays and php would iterate it for me but what should I do in javascript?
Thanks

Just pass the array. jQuery will encode it with array notation, and PHP will decide it back into an array:
jQuery.post(MyAjax.ajaxurl,
{ action : 'ajax-rform',
link: fileLinks
},
function(data){
jQuery("#fileupload").after('<h1>Success</h1><p>Your registration has been recieved.</p>');
});
In PHP, you can access the array as $_POST['link'].

Why not just create a json array and then use php's json_decode method?

Perhaps you should just make a data object to send, populate it from your array like this
var postData = { action : 'ajax-rform' };
for(var i = 0; i < fileLinks.length; i++){
postData["link"+(i+1)] = fileLinks[i];
}
And then use that in your ajax
jQuery.post(MyAjax.ajaxurl,
postData,
function(data){
jQuery("#fileupload").after('<h1>Success</h1><p>Your registration has been recieved.</p>');
}
);

passing JSON data and getting it back

I'm new to passing objects through AJAX, and since I am unsure of both the passing and retrieving, I am having trouble debugging.
Basically, I am making an AJAX request to a PHP controller, and echoing data out to a page. I can't be sure I'm passing my object successfully. I am getting null when printing to my page view.
This is my js:
// creating a js filters object with sub arrays for each kind
var filters = {};
// specify arrays within the object to hold the the list of elements that need filtering
// names match the input name of the checkbox group the element belongs to
filters['countries'] = ["mexico", "usa", "nigeria"];
filters['stations'] = ["station1", "station2"];
filters['subjects'] = ["math", "science"];
// when a checkbox is clicked
$("input[type=checkbox]").click(function() {
// send my object to server
$.ajax({
type: 'POST',
url: '/results/search_filter',
success: function(response) {
// inject the results
$('#search_results').html(response);
},
data: JSON.stringify({filters: filters})
}); // end ajax setup
});
My PHP controller:
public function search_filter() {
// create an instance of the view
$filtered_results = View::instance('v_results_search_filter');
$filtered_results->filters = $_POST['filters'];
echo $filtered_results;
}
My PHP view:
<?php var_dump($filters);?>
Perhaps I need to use a jsondecode PHP function, but I'm not sure that my object is getting passed in the first place.

IIRC the data attribute of the $.ajax jQuery method accepts json data directly, no need to use JSON.stringify here :
data: {filters: filters}
This way, you're receiving your json data as regular key/value pairs suitable for reading in PHP through the $_POST superglobal array, as you would expect.

http://blog.teamtreehouse.com/beginners-guide-to-ajax-development-with-php
When you use ajax the page is not reloaded so the php variable isn't of use.
You may want to look for a tutorial to help. I put one at the beginning as I don't see how to format this on my tablet
you will need to json_encode your response as the tutorial shows
you may want to print to a log on the server when you are in the php function and make it world readable so you can access it via a browser
I like to use the developer tools in Chrome to see what is actually returned from the server