Take Control Of Web Control ClientID Values in ASP.NET 4.0
Each server-side Web control in an ASP.NET Web Forms application has an <code>ID</code> property that identifies the Web control and is name by which the Web control is accessed in the code-behind class. When rendered into HTML, the Web control turns its server-side <code>ID</code> value into a client-side <code>id</code> attribute. Ideally, there would be a one-to-one correspondence between the value of the server-side <code>ID</code> property and the generated client-side <code>id</code>, but in reality things aren't so simple. By default, the rendered client-side <code>id</code> is formed by taking the Web control's <code>ID</code> property and prefixed it with the <code>ID</code>
