Could someone tell me how to use radio/checkbox to control the display of
text field or button. For example, when click on radio, one text field related
to it will show up. I tried the following way, but the text field showed
in a new window, not next ot the radio.

<input type=radio name="first" onclick="addfield()">
<script LANGUAGE="JavaScript">
document.writeln("<b>Re-enter</b><input type=text name=\"pass\"><br>");

Any help is appreciated!