title: When would you use a Web User Control over a Web Custom Control?
body: <p>Can someone explain when to use each of these?  They almost seem interchangeable in many cases.  </p>
  
  <p>The Custom Control gets added to the toolbar while the User Control (ascx) can not.  The Custom Control does not get rendered in the Designer while the User Control does.  Beyond that, how do you choose which is the right one to use?  </p>
  
  <p>Also, I am looking for the best way to access the controls from JavaScript (GetElementById).  So, a point in the right direction for adding client side support would be great.</p>