This is part of the MSIE data binding support. It contains the name of an ODBC data source (which might be any kind of SQL database that supports such an adapter). The data source and element are bound together with each column of the data source providing a source value to different element objects through their dataFld property.
Normally, both the dataFld and dataSrc values would be defined with the DATAFLD and DATASRC HTML tag attributes in the document source.
Setting both the dataFld and dataSrc properties to an empty string will disconnect the element from the database.