echo do_shortcode for Contact Form 7 from within dynamically loaded php file

Question

I am loading a php file containing echo do_shortcode('[contact-form-7 id="568"]'); using jQuery .load() but the shortcode returns nothing.

I have seen this question and answer and understand that do_shortcode() isn't available: Why might a plugin's 'do_shortcode' not work in an AJAX request?

But I'm afraid I can't for the life of me figure out if the solution is relevant to my setup.

Hoping someone can help shed some light.

Thank you.

script.js

$.post(themeurl+ 'save_image.php', { base64_image: ProductDataURL }, function(data) {
    if(data) {
        $( '#popup-download div' ).load( themeurl+ 'downloadform.php' );
    }
});

downloadform.php

<?php
if ( function_exists( 'do_shortcode ' ) )  {
        echo "do_shortcode exists";
} else {
        echo "do_shortcode doesn't exist";  // this gets echoed
};
echo do_shortcode('[contact-form-7 id="568"]'); // nothing
?>

Answer 1

From what you have shown, downloadform.php never loads WordPress, hence naturally do_shortcode() is not available.

You need to implement your AJAX using this Codex article: http://codex.wordpress.org/AJAX_in_Plugins

Another alternative I would suggest is loading the contact form in a hidden div during the initial page load and then display the hidden div when users click whatever makes the form pop up. That way you don't need any AJAX at all.