Código HTML:
<p>
<map name="FPMap1">
<area href="#" onClick="window.open('principal.html','','width='+screen.width+',height='+screen.height+' ,resizable=yes ,top=0,left=0')"" shape="rect" coords="93, 4, 215, 23">
</map>
<img border="0" src="arq_estrutura/bot_entrar.gif" width="304" height="50" usemap="#FPMap1"> </p>
<p> principal.htm es el popup