The RadInputManager offers an easy and intuitive way to extend a standard asp.net text box, and without any extra custom code, introduce much functionality, normally related to a Telerik RadInput control. For example, a standard text box control offers no default functionality for text parsing and validation – this has to be done via custom code, either client or server side. This input validation is normally associated with Telerik RadInput controls.
On the other hand, having a large number of input controls on the page may hurt performance. This is where the RadInput Manager comes in. It automatically adds extra functionality to separate text boxes, or all text boxes nested in another control on the page, via a few settings added to the Input Manager.
One of the differences between text boxes extended via the Input Manager, and normal RadInput controls is that there are no additional buttons, such as a spin button.
The client event model for the Input Manager is similar to that of the normal Telerik RadInput controls, whereas the server side model offers one additional event (other than the events available for the text boxes), where certain settings can be altered.
To summarize, the RadInputManager offers extended functionality to standard text boxes, with little overhead related to increased page footprint, or extra coding.