You Just need to set the Viewport
Make a Link like you said, and this link is a reload of the page but with a ?desktop_viewport=true, then you can set a Session and as long as that session is set you write this
<meta name="viewport" content="width=1024">
Instead of this (Responsive version)
<meta name="viewport" content="width=device-width, initial-scale=1.0">
In your <head>
Use this as a button
<a href="https://stackoverflow.com/questions/22405816/mywebsite.php?show_desktop_mode=true">I want desktop mode!</a>
And insert this at the top of your php-file (witch must be loaded on every page)
<?php
session_start();
if($_GET['show_desktop_mode'] == 'true') {
$_SESSION['desktopmode'] = 'true';
}
?>
After doing that, you have to change the viewport according to the Sessionvalue by doing this in <head>
<?php
if($_SESSION['desktopmode'] == 'true') {
/* DESKTOP MODE */
?>
<meta name="viewport" content="width=1024">
<?php
} else {
// DEFAULT
?>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<?php
}
?>