Increasing accuracy in determining purpose of fields in forms

An arrangement for increasing the accuracy in determining the purpose of fields in electronic forms is disclosed in which a form mapping mechanism describes the layout of a form, for example, by identifying the location of objects on a form-such as text-entry fields, drop-down menus and the like that are used to record user data-and further by specifying the purpose of those objects to a form filling client. Form mapping enables the form filling client to locate and understand the purpose of fields in a form so that it may automatically fill out forms for users in an accurate and reliable manner. Illustrative examples include a form mapping that utilizes hidden tags to describe a form layout, a form mapping service provided to a form filling client over a network, and a user interface that enables form mapping creation through user action.