creo que sería algo como esto
![apachar ojo](http://static.forosdelweb.com/fdwtheme/images/smilies/wink.png)
![apachar ojo](http://static.forosdelweb.com/fdwtheme/images/smilies/wink.png)
function refop2(e) {
tecla = (document.all) ? e.keyCode : e.which;
qnum = document.refip.Submit.value
opera = foper(qnum);
clearTimeout(bl);
switch (opera) {
case '1' && tecla==13 : window.open('index1.html','','width=200,height=200 ');
break;
case '2' && tecla==13 : window.open('index2.html','','width=200,height=200 ');
break;
case '3' && tecla==13 : window.open('index3.html','','width=200,height=200 ');
break;
default:
break;
}
return "";
}