Further investigation in the API technical documentation reveals the existance of a class named MdsCompliantAttribute in the Microsoft.SharePoint.WebControls namespace. This value indicates whether the script, style, and field registrations of a class are compliant with the Minimal Download Strategy (MDS) framework. There is not a lot of documentation about this Minimal Download Strategy framework other that it being very similar to Ajax asynchronous loading.

The similarity to Ajax is hinted at with the following remark in the details of this MdsCompliantAttribute class:

This custom attribute class should only be applied when all registrations—such as scripts and styles—are performed through the SPPageContentManager class methods. All controls that render inside an AjaxDelta control must either have this attribute or be in a whitelisted assembly for which all controls are compliant.

Further details on the SPPageContentManager class indicates the following note:

Manages all the resource content that may be registered on a SharePoint page, including script files, inline scripts, style files, inline styles, and hidden input fields. Spweb Ensures that the content can be either appropriately placed on a fully-rendered HTML page or correctly transmitted to a browser in the case of a partial page load.

Hopefully this MDS framework will allow for faster load times for the end users by reducing the amount of full page refreshes required while browsing around. AjaxDelta seems to indicate loading the destination’s required files asynchronously but only the ones that are not loaded in the current page. Again, this is supported by the partial page load indication and the Delta word attached to Ajax.

More to come in other parts of this series.