This is the string or other data type passed as extra arguments to a modal dialog window created with the window.showModalDialog( ) or (in IE 5 and later for Windows only) window.showModelessDialog( ) methods. This property is best accessed by a script in the document displayed in the dialog window in order to retrieve whatever data is passed to the new window as arguments. It is up to your script to parse the data if you include more than one argument nugget separated by whatever argument delimiter you choose.