Please explain about Ajax Timer Control.

Timer Control is one that calls a C# function in timed intervals. This is a perfect application for bringing in information based on a timer but not reloading the entire page.
Timer Properties: - Not only is the Ajax Timer control useful, but it also is easy to use. With only four properties, ID, Enabled, EnableViewState, and Interval, we can set it up very quickly. For most application the only property that really needs setting is the Interval. The Interval value is set in microseconds. So, for example, if we want a 22 – second interval, we would set the value to 22000.
The control has several different events as well, but for most uses, all we need is the OnTick event. The OnTick event calls a C# event handler (method) at the assigned Interval. By placing the Timer inside UpdatePanel container, by default it is the Ajax event handler for the UpdatePanel.