This is part of the MSIE data binding mechanism that associates a column name in the data source with the value property of an Input object. You must also set the dataSrc property for the object. Normally, both the dataFld and dataSrc values would be defined with the DATAFLD="..." and DATASRC="..." HTML tag attributes in the document source.
Note that the value is case sensitive and must refer to a column that exists within the data source.
Setting both the dataFld and dataSrc properties to an empty string will disconnect the element from the database.