One possible form that you might consider using Ajax is a comment form. Users love to see their comments immediately posted without having the page reloaded for them. Ajax is still somewhat confusing for users, which means you need to build in a few strong feedback mechanisms. First, let’s build a really simple contact form with just a username field, comment field, and a submit button.
<div>Comments</div> <form id="commentForm" action="comment-post.php" method="POST"> <input id="commentUsername" type="text" name="username" /><span id="commentUsernameError">sdfasdf</span> <textarea id="commentComment" name="comment"></textarea><span id="commentCommentError">sdfdsfa</span> <input type="submit" id="commentSubmit" name="action" value="Submit" onclick="return false;" /> <div id="commentFeedback" style="display:none;"><img src="loading.gif" /></div> </form>