Radio buttons

<input type="radio" name="dis" value="radio">
District
<br>
<input type="radio" name="niv" value="radio">
Niveau
<br>
<input type="radio" name="onder" value="radio">
Ondergrond
<br>
<input type="radio" name="periode" value="radio">
Periode
<br>
<input type="radio" name="ver" value="radio">
Vereniging

<form method="post" action="">
<p>Zoeken naar:
<input name="zoekwoord" type="text" size="40"/>
</p>
<p>Zoek op:<br>
</p>
<p>
<input type="radio" name="dis" value="radio">
District
<br>
<input type="radio" name="niv" value="radio">
Niveau
<br>
<input type="radio" name="onder" value="radio">
Ondergrond
<br>
<input type="radio" name="periode" value="radio">
Periode
<br>
<input type="radio" name="ver" value="radio">
Vereniging
</p>
<p>
<br>
<br>
</p>
<p>Als u Periode hebt geselecteerd, moet u dit vak invullen:</p>
<p>
<input name="periode" type="text" id="periode" value=" dag maand jaar" size="40"/>
<br>
<br/>
<input type="submit" name="submit" value="Zoek"/>
</p>
</form>