Call procedure in the OnClick area of the Image Map in ASP.NET

Good afternoon, I have this code:

<img src="../Image/sala.png" USEMAP="#sala" BORDER=0> 

<area name="window" shape="poly" coords="633,82,631,117,627,145,625,160,644,162,671" href=""  alt="window" title="" OnMouseOver="window.status='window'; return true" OnMouseOut="window.status=''; return true">

I have a sub in vb that calls a dialog box that wanted to be called in onclick from the above code. Someone can help me? Thanks:)