This control is most commonly used to create a 'save' button, which posts the XML data associated with the current mash to the CGI specified in its url attribute. In order for the mash and clip tags that make up the mash to be included in the request, the mash attribute must be set to '1' and the tie attribute set to 'player.mash'. The referenced media and font option tags can also be included in the request by setting the media attribute to '1' as well. This generates what might be called a 'fat' mash - a self contained file that can be displayed in a simple player. Learn more in Mash Saving.

The control can also be used to create more generic forms, though the total amount of data that can be passed to the CGI script is limited because parameters are sent via the GET method. To use this approach the url attribute is dynamically populated with values from other controls in the interface, or from the CGI control itself which supports binding to arbitrary properties.

Regardless of how the CGI control is initially configured, it can be partially reconfigured based on the response it receives from the server side script. For instance, a javascript alert could be displayed by returning a tag with its get attribute set to 'javascript:alert("Hello world!");'. Or the Player could be activated by setting the trigger attribute to 'player.play' and the value attribute to '1'.

If the response contains a url, upload or download attribute it will be requested without further user interaction. A delay attribute can also be specified so the requests can be staggered if needed. This mechanism allows one CGI script to trigger another and another, so a single process can span over consecutive requests. This is useful for tracking asyncronous server tasks like processing of media files after uploading. The control also supports the progress and status attributes, which can be bound to a Slider and Text control for visual feedback.