if ( document.form_1.platform.id == 'required') {

document.writeln('<p><b>* What is your primary platform? </b><br/>'); 

document.writeln('<input type="radio" value="&lt;value&gt;Windows&lt;/value&gt;" name="system">Windows<br/>'
+ '<input type="radio" value="&lt;value&gt;Linux&lt;/value&gt;" name="system">Linux<br/>'
+ '<input type="radio" value="&lt;value&gt;Mac&lt;/value&gt;" name="system">Mac<br/>'
+ '<input type="radio" value="&lt;value&gt;SGI&lt;/value&gt;" name="system">SGI<br/>');
}