Standard file selector.

that have this behavior applied by default:

• <input type=“file” /> - inline single line
• <widget type=“file”></widget>

These elements placed inside <form enctype=“multipart/form-data”> will cause content of the selected file to be sent to the server.

that this behavior knows about:

• filter=“filename-filter” - defines list of file name filters. filename-filter is list of filter groups separated by semicolon ';' where each group contains filter name, ':' and comma separated list of file masks. Sample:

  <input name="uploadedfile" type="file" 
         filter="HTML files:*.htm,*.html;Text files:*.txt;All files:*.*" 
         novalue="(select file)"/>

• novalue=“text” - if file was not selected (the input is empty) then it shows text provided by the novalue attribute. You can style this state by using :empty CSS selector.

Together with the standard set of events (mouse, keyboard, focus) behavior: file generates:

• BUTTON_STATE_CHANGED event - value of the element was changed due to user actions. Posted (asynchronous) event.

type json::value::V_STRING, reports filename selected.

Note that the value is read-only by code. Only user can set the value from UI. That is made intentionally to prevent arbitrary files to be sent from user's computer.