API response is blank when viewed in a browser

If you create a web page that sends a message to a user and displays the API response, when you view that page in your browser, you will see a blank page.

The API response for sending a message is entirely in XML with no text content. The browser interprets this as HTML and has nothing to display. Viewing the source of the page will reveal the API response. You may also wish to entity encode the response prior to display in a browser. Replace < with < before you display the response and you'll be able to see the text.