Q:

How to create a button in WordPress that emails the URL of the current page?

How can I make a button that, when pressed, sends an e-mail link with current page on WordPress? I know there is a plugin, but I would like to know how to do it by myself.
Something like this:
$(function(){
    $('button').click(function(){
        $.ajax({
            data: 'action',
            url: '...'
        }).done(function( response ){
            $('button').html('Thank you');
        })
    })
})

And PHP:
if( $_POST['action'] =='action'){
    mail("joecool@example.com", "My Subject", "text");
}

A:

functions.php
wp_register_script( 'myscript', path/to/script.js, array( 'jquery' ));
wp_localize_script( 'myscript', 'ajaxobj', array('ajaxurl' => admin_url().'admin-ajax.php') );
wp_enqueue_script( 'myscript');

script.js
$(function(){
     $('button').click(function(){

     var admin_url = ajaxobj.ajaxurl;

     $.ajax({
         type:'POST',
         data: {action: 'mail_func', name: 'danish'},
         url: admin_url
     }).done(function( response ){
         $('button').html('Thank you');
     })
 })
})

And PHP (functions.php)
 add_action( 'wp_ajax_mail_func', 'mail_func_callback' );
 add_action( 'wp_ajax_nopriv_mail_func', 'mail_func_callback' );

 function mail_func_callback(){
     $Name= $_POST['name']; //danish
     wp_mail( $to, $subject, $message, $headers, $attachments );
     die();
 }

