php html_entity_decode and htmlspecialchars_decode not working [duplicate]

I have a preview page or an email that is created with html and php. So basically on this page there is a big $body string that can contain any html and php. But I want to send this string to another page with a link:

echo '<a href="[theURL]?body='.htmlentities($body).'">Click here</a>';

the link goes to a second php page that should display everything the same was as on the first page:

<?php
    if(isset($_GET["body"])){
        echo html_entity_decode($_GET["body"]);
        //echo htmlspecialchars_decode($_GET["body"]);
    }
?>

the second page gets the string in the url, but remain empty. so either it's not decoding it right or i missed something simple? the url looks something like this: %20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20

Is there a better way to do this than $_GET? I tried to use a form instead of a link and use post, but it didn't seem to work.