The most widespread accessibility failure in web forms is using placeholder text instead of labels. Placeholder text is the light gray text that appears inside an input field before someone starts typing. It disappears the moment a user clicks the field and starts entering information. For sighted users with good working memory, this is a minor inconvenience. For users with cognitive disabilities, users who are completing a long form slowly, or users who need to go back and check what a field was asking, disappearing placeholder text creates real barriers. Every input field needs a visible, persistent label that does not disappear.
Error messages need to be specific and actionable. An error message that says Invalid input or This field is required tells the user that something went wrong without telling them what to do about it. An error message that says Please enter your email address in the format name@example.com gives them the specific information they need to correct the problem. Screen readers announce error messages to blind users, so the message needs to make sense when read aloud without the visual context of the field it belongs to. Associate error messages with their fields using ARIA attributes so screen readers announce the error when the user reaches the field.
Required fields need to be marked consistently. The convention is an asterisk with a note at the top of the form explaining that asterisk means required. Do not use color alone to indicate required status because users with color blindness will not be able to distinguish required from optional fields. Do not make every field required unless every field genuinely is. Unnecessarily required fields increase abandonment rates for all users and create additional burden for users with disabilities who may take longer to complete each field.
Keyboard navigation must work throughout the entire form. Tab moves focus forward through interactive elements, Shift Tab moves backward, Enter or Space activates buttons. Test this by unplugging your mouse and completing your form using only the keyboard. Focus indicators, the visible outline that appears around the currently active element, must be visible at every step. Browsers provide default focus indicators, but many designers override them with CSS because they find them visually unpleasant. Removing focus indicators makes the form unusable for keyboard-only users.
Form timeout handling requires specific attention. If your form session times out due to inactivity, users who take longer to complete forms including those with motor impairments or cognitive disabilities may lose their work. If a timeout is necessary, warn users before it occurs and give them a way to extend their session. If the form is for collecting information rather than processing a time-sensitive transaction, consider whether a session timeout is necessary at all.
An accessible form is not a specialized accommodation for a small percentage of users. It is a well-designed form that works correctly for every user, and the principles that make forms accessible also make them clearer, easier to complete, and less prone to submission errors for everyone.