/**
 * Hide the form submit button and display an optional wait message.
 * @param {String} wait_message
 */
function hide_submit_button(wait_message) {
	var submit_button = document.getElementById('inquiry_submit_button');
	submit_button.style.display = 'none';
	document.getElementById('submit_wait_message').innerHTML = wait_message;
	return true;
}