Saludos!
Código HTML:
<html> <head> <meta http-equiv="content-language" content="es"> <title>Alta de alumnos.</title> </head> <body> <script language="JavaScript"> function yesnoCheck() { if (document.getElementById('yesCheck').checked) { document.getElementById('ifYes').style.visibility = 'visible'; document.getElementById('ifNo').style.visibility = 'collapse'; } else document.getElementById('ifNo').style.visibility = 'visible'; document.getElementById('ifYes').style.visibility = 'collapse'; } </script> <li><label for="Proceso">Compañia:</label><ul> <li><input class="iradio" type="radio" checked="checked" onclick="javascript:yesnoCheck();" name="yesno" id="yesCheck"> <label for="Proceso2" class="ilabel">Si</label></li> <li><input class="iradio" type="radio" onclick="javascript:yesnoCheck();" name="yesno" id="noCheck"> <label for="Proceso3" class="ilabel">No</label></li> </ul></li> <div id="ifYes" style="visibility:visible"> <li><label for="ficha">N° Ficha:</label><input class="itext" type="text" name="ficha" id="ficha" /></li> </div> <div id="ifNo" style="visibility:collapse"> <li><label for="curp">CURP:</label><input class="itext" type="text" name="curp" id="curp" /></li> </div> </body> </html>