Use Ajax/JavaScript effects sparsely on your forms only when necessary. Don't hide important information behind fading JavaScript effects unless it is very intuitive and adds to the user's experience.
Labels are very important.
Aggressive client-side validation can lock users out while revealing your business logic.
For file uploads, the basic file uploads are horrible for uploading multiple files and styling, consider SWFUpload or a Java uploader like Facebook.
Marc wrote:
Yes, yes and yes. Great post on coding forms.
Use Ajax/JavaScript effects sparsely on your forms only when necessary. Don't hide important information behind fading JavaScript effects unless it is very intuitive and adds to the user's experience.
Labels are very important.
Aggressive client-side validation can lock users out while revealing your business logic.
For file uploads, the basic file uploads are horrible for uploading multiple files and styling, consider SWFUpload or a Java uploader like Facebook.