WordPress: How to use Ajax at front side without using admin-ajax.php

Mostly all wordpress developers write the code to create widgets in admin side. and he use following code:

  	var ajaxurl ='';

        var data = {
		action: 'action_function_name'
	};
   
	// since 2.8 ajaxurl is always defined in the admin header and points to admin-ajax.php
	jQuery.post(ajaxurl, data, function(response) {
		alert(response);	
	});

But when he wants to use Ajax at front side without login in Admin side area. then admin-ajax.php file will not run because it is made for only admin. so here I am providing solution:
Just create a new file front-ajax.php and put below code inside the file:

And use front-ajax.php rather than admin-ajax.php in your code. This code is running well at my side.