Detect users input values from any wordpress form - wordpress

Question

I'm trying to develop a wordpress plugin, I need to get users input data from any form in a specific page (not knowing its action) I come up so far with this solution which is to get values using javascript and then passing it to php:
jQuery(function ($) {
$(document).ready(function(){
$( "form" ).submit(function( event ) {
if($( "form" ).valid()){
var inputs = $( "form input" );
var inputValues = [];
inputs.each(function(index){
if($(this).attr('type') !== 'submit')
inputValues.push($(this).val());
});
}
event.preventDefault();
});
});
});
I tried to pass the Javascript variable inputValues to my plugin using Ajax
$.ajax({
type: 'POST',
url: '../wp-content/plugins/myplugin/myplugin.php',
data: {'variable': inputValues},
});
But I get problems with the url for some pages and I couldn't use $_POST['variable'] in myplugin.php file.
Is there a way to accomplish what I'm trying to do, or do you know an alternative solution?
Thanks in advance.

Answer 1

in terms of how to implement AJAX calls using WordPress, please check out the WordPress Codex. You're not doing it correctly.
JavaScript seems like a round about way of doing this. I would suggest to hook into one of hooks that are being called almost every single time like template_redirect (https://codex.wordpress.org/Plugin_API/Action_Reference/template_redirect).
Then you can check what's in the $_POST variable and do what you need to do with it. This would even Capture AJAX forms as long as the URL links to a proper AJAX WordPress endpoint.
Hope this helps