Pasting Leadpages script into Perch

Hi, we use a thing called Leadpages which allows us to have a button which people click, enter the email address and a specific brochure is sent to them. This allows us to capture leads for potential customers.

We wanted the buttons on our website and can do this by pasting the code below. After 1 save, the button looks ok and works on the site but if we were to edit the page again and resave, the script is removed and the button changes to a plain text link. Is there any way to get around this? Or everytime we edit a page with a button, do we have to repaste the code?

Thank you

<script src="//static.leadpages.net/leadboxes/current/embed.js" async defer></script> <button data-leadbox-popup="146d6e573f72a2:14fe272c4f46dc" style="background: #32C88C;border-color: #32C88C;border-radius: 0px;color: #FFFFFF;display: inline-block;vertical-align: middle;padding: 16px 32px;min-width: 192px;border: 1px solid #32C88C;font-size: 1rem;font-family: Helvetica, Arial, sans-serif;text-align: center;outline: 0;line-height: 1;cursor: pointer;-webkit-transition: background 0.3s, color 0.3s, border 0.3s;transition: background 0.3s, color 0.3s, border 0.3s;">Click here to subscribe</button>