Modal MessageBox for ASP.NET without jQuery
<p>I have an assembly with custom ASP.NET server controls that is used in several, mostly in-house, ASP.NET 2.0 applications.  The server controls use simple modal popup messageboxes, which are currently implemented using the javascript <strong>alert</strong> and <strong>confirm</strong> functions.</p>

<p>I want to release a new version of this assembly that uses a better solution for messageboxes, including support for Yes/No buttons.  </p>

<p>Ideally the appearance would be something like a simplified version of the Ajax Control Toolkit ModalPopup extender (<a href="http://www.asp.net/ajax/ajaxcontroltoolkit/Samples/ModalPopup/ModalPopup.aspx" rel="nofollow">sample here</a>).</p>

<p>My constraints are that this should be as easy as possible to integrate into existing ASP.NET 2.0 applications without introducing new dependencies: ideally just drop in a new version of the assembly, that contains all the javascript it needs as an embedded resource, and possibly a CSS file.</p>

<p>Because of this constraint, I am not considering solutions I've seen that use jquery, or the ASP.NET Ajax Control Toolkit, which appears to require adding elements to pages that use the extenders (ScriptManagers and the like).</p>

<p>Any recommendations?</p>
