function iSubmitEnter(oEvento, oFormulario){ 
     var iAscii; 

     if (oEvento.keyCode) 
         iAscii = oEvento.keyCode; 
     else if (oEvento.which) 
         iAscii = oEvento.which; 
     else 
         return false; 

     if (iAscii == 13) __doPostBack(oFormulario,'');   

     return true; 
}