A few other points that you should consider to make sure that everyone can successfully complete and submit your forms:
- Keyboard accessibility: ensure that all parts of a form can be reached in a logical order and activated by a keyboard as well as a mouse.
- Information structure: arrange text so that key or unique words , phrases or sentences come first. This is vital when creating forms, as it may affect the length of time that it takes the user to understand what is required of them.
- Timeout: where it's necessary to apply a session timeout to a form, a mechanism will need to be provided to give the user some control over the time limit.
- Moving focus: don't use script to move the keyboard focus position if at the same time it changes the context, (for instance changes the page or subject.
- Tab order: Ensure that the tab order is logical through all form controls and links within the form, including the submit button. If using the tabindex attribute, ensure that the tab order of the entire form is checked before it's published.