Develop Reference

Load php file within javascript (AJAX or others)

I am trying to finish one page of my website the last couple of hours while achieving the following.
While clicking on a button, the following should happen
Download link appears (done - works)
The mySQL table should be opened and a counter should be incremented
As far as I got the points. Javascript cannot handle that and thus we can use AJAX or jQuery. I was already checking out different posts and websites such as:
how to execute php code within javascript
https://www.w3schools.com/js/js_ajax_database.asp
and much more. However, I guess I do have problems with the AJAX syntax and I actually don't know if the requested php files is loaded/opened or not. Especially the second link given above is almost similar to what I am searching for. However, it does not work. To check if the php file is called, I set an alert which works if I do call the file explicitly in the browser. Maybe this does not work with AJAX as I expect it. Here the code to get more familiar with the inconstency I am doing.
The page code:
<?php
echo '<div><button onclick="incrementAndDownload('testPath', 'fileName'); ">Click me</button></div>';
?>
<script>
function incrementAndDownload (link, fileName)
{
$.ajax({
url: 'openfoam/increment.php',
success: function(data) {
// Print something if necessary
}
});
//- Open the link
// window.open(arguments[0], "_blank");
//- Increment download inside mysql
//var xhttp;
//xhttp = new XMLHttpRequest();
//xhttp.open("GET", "openfoam/increment.php?foo=nana", true);
//xhttp.send();
}
</script>
The increment.php looks as follows:
<?php
echo '<script type="text/javascript" language="Javascript">
alert("Test message if the script is called...");
</script>';
// Code for accessing the mysql database and manipulate the data
//$page_id = mysql_real_escape_string(html_entities($_POST['file']));
?>
Now when I click the button, the javascript is executed (e.g., if I uncomment the window.open) this works as expected. However, as already said, the second part is to open the database via php and increment a number (counter). For any reason, I am not able to figure out where the problem is located. I am even not sure if AJAX opens the increment.php file (the alert messages never appears so I guess it is never called). Any suggestion is appreciated and I hope that this question does not just contain a fundamental small error. Thank in advance, Tobi

It's not the way the AJAX works. If you call alert() on a destination page it won't show in your browser. Your case is very basic so I will keep my solution on a basic level.
In increment.php just echo something, it can be just OK string. So when you go to increment.php page you will see only OK, nothing more, nothing less.
Then go back to your javascript and check what is your response.
$.ajax({
url: 'openfoam/increment.php',
success: function(data) {
if (data == 'OK') {
console.log('It works, sir!');
}
}
});
If you don't see a message in a console after these modifications something doesn't work. However, I think your page is executed properly, but you just don't get feedback, because you don't handle the response (data param in your case).
Check it out and don't forget to give me a feedback!🤓

Wordpress get post id with a php file

I have been stuck on this for weeks. I have an HTML slide presentation using Reveal.js. I want to run a php script on the very last slide.
This is an HTML button on the last slide within a Wordpress post:
<button onclick="myFunction()">Open php file</button>
<script>
function myFunction() {
window.open("../../testing/test.php", "_self");
}
</script>
This is the code inside the test.php file that I am trying to run but it returns null:
define('WP_USE_THEMES', false);
require_once('../wp-load.php');
echo "Post ID: ".get_the_ID(); // Returns nulls but I want this to return 86.
The post id is 86. I can hard code it into the html (if I have to) but I don't want to hard code it into the php file. Also, I would prefer not to use jquery. How can I get the post id into the php file? Thanks.

Have you tried using global $post variable??
global $post;
And after that, you can get the id,
echo "Post ID: ".$post->
Another approach is using $wpdb global variable to make database queries.
You can also use JavaScript to send your post id to another php file using javaScript forms, Ajax or jQuery. jQuery Post.
Maybe the most easiest approach for you is something like this
function myJavascriptFunction() {
var javascriptVariable = "John";
window.location.href = "myphpfile.php?name=" + javascriptVariable;
}
On your myphpfile.php you can use $_GET['name'] after your javascript was executed.

Button On click call jquery function and acess php

I am very new to Wordpress and Woocommerce. I have few doubts wrt jquery in Wordpress. Say i have a function
function test(){
alert("test");
<?php
error_log("Test ---------------------------- ", 0);
?>
}
and a button:
<input type="button" id="btnclick" onclick="test();" value="Test" />`
error log is printing on page load but not on click. But i want to execute code inside php block only when user clicks on button.Is there a way to achieve this ? Thanks in advance`

jPO has already explained how to solve this in a good way, but I thought I should explain why this happens.
PHP is executed on the server. Once the page has been sent to the client, the PHP is no more. JavaScript happends on the client, and can be executed as long as the user is viewing the webpage. Since they do not live during the same timeperiod they are not aware of each other and can not be mixed in that way.
When you visit the page in your browser, the browser sends a request to the server. On the server the PHP interpreter goes through the code of the requested page, executing everything between <? and ?>. It does not understand what the other stuff around it is - it could be HTML, JS, plain text, anything, the PHP interpreter does not know and does not care. That is why it writes to the error log on page load.
When the PHP interpreter is done it has produced a document looking like this:
function test(){
alert("test");
}
That is sent to the client, and the JS (without any instruction to write to the error log) is run on the client when the button is pushed.

Not possible like that. If you'd like to do so. You need something like ajax method in php which you can call. Let's say you have a file in the root of your project called ajax.php, there you can define a function named test(), then you have to have a $_REQUEST translator, which calls your function test(), so the ajax.php would look like this
<?php
// checks if you sent a parameter named method and calls the method
// if you provide parameter named params it will send them too
if(isset($_REQUEST)){
if(isset($_REQUEST["params"]))
ajax($_REQUEST["method"],$_REQUEST["params"]);
else
ajax($_REQUEST["method"]);
}
function ajax($function,$data = null){
$function($data);
}
function test(){
error_log("Test ---------------------------- ",0);
}
and your ajax would look like this
function test(){
$.ajax({
url:"ajax.php",
data:{
method:"test"
}
});
}
hope it helps

A method to pass a variable to Javascript currently run in the header

Please excuse me ignorance, I'm completely new to Javascript.
I have this code that is currently run in the header, however I need to pass it $_GET variables before it runs.
jQuery(document).ready(function() {
refresh();
jQuery('#bittrex-price').load('http://<site>/realtime/bittrex-realtime.php?symbol=ltc');
jQuery('#mintpal-price').load('http://<site>/realtime/mintpal-realtime.php?symbol=ltc');
});
function refresh() {
setTimeout( function() {
jQuery('#bittrex-price').fadeOut('slow').load('http://<site>/realtime/bittrex-realtime.php?symbol=ltc').fadeIn('slow');
jQuery('#mintpal-price').fadeOut('slow').load('http://<site>/realtime/mintpal-realtime.php?symbol?ltc').fadeIn('slow');
refresh();
}, 10000);
}
It's pretty simple, all it does is pull the latest price from another PHP script.
I need to append a $_GET variable to the URL as current I have no way to change the ?symbol=ltc depending on which page the user is visiting. Because Wordpress is being awkward, I've had to save this function in a .js file and add a hook in functions.php otherwise it won't load at all. Ideally, I'd like to be able to run the function in the body so I can modify, but I can't get that to work either :/
I hope this makes sense, I'm open to any suggestions as I'm clearly missing the point somewhere here.
Thanks

You need to use the language that is building the web page to output some javascript for use in your functions.
Thus, if you're using PHP to build your page you could do something like this in the <head> section of your page:
<?php
print '<script>';
print 'var symbol = ' . $_GET['your_get_variable'] . ';';
print '</script>';
?>
Then, in your later javascript code you have your GET variable string stored in 'symbol' and can use it however you like.
The 'your_get_variable' is what is coming in via the query string in the URL that got you to the current page. Just make sure you put this code above where you want to use 'symbol' in your later javascript.
Also, It's not really a good idea to use $_GET data directly like that without some validation, but I'm just keeping the example clean.

JQuery/AJAX: How to pass variables to some JS-API?

I have a problem with passing JS-defined Variables from an AJAX response to a JS-API, namely Googles jsapi. What I want to do is display a chart using this API and then use AJAX from time to time to reload the values from a database.
So far, everything works just fine. But as I return these variables by AJAX - how can I get JS to parse the result?
The code:
<div id="t">
xyz
</div>
<script>
window.setInterval(function()
{
$.post('mod/script.php', function(data) { $('#t').html(data) } );
}, 5000);
</script>
Where script.php would return values like
echo "data.addRows($datasets);";
echo "data.setValue($i, 0, '$date $time');";
Problem is, that I dont know, which values are returned by the script. This depends on what is currently stored in the database.
How to do this right? I have some ideas, but I wonder what is the most convenient way here...

If I get you right, you want to execute certain JS callbacks in the context of the current document, is that right?
The proper way would be JSONP.
A really really really quirky "alternative" would be to do this in your script.php:
echo "(function(){";
echo "data.addRows($datasets);";
echo "data.setValue($i, 0, '$date $time');";
echo "})()";
and have this callback:
$.post('mod/script.php', function(callback){ eval(callback); });
Also, see this fiddle: http://jsfiddle.net/EsytA/1/