show hide list boxes

I am trying to hide or show an entire list box based on what the user selects and i am not entirely sure how to do it.
i am wanting the user to select either school or city in the first list and based on the decision i want the following list box to appear.
I am not sure if radio buttons would be better because i don't know anything about them.

form name="school">
    <select name="type">
            <option value="school" selected="selected">School</option>
            <option value="city">City</option>
    </select>
    <select name="school">
    	<option value="North Central MO College" selected="selected">North Central MO College</option>
    </select>
    <select name="city">
   	  <option value="Trenton" selected="selected" >Trenton</option>
  </select>

</form>

PHP:

thanks

 

Not Tested!!

<form name="school">
    <select name="type">
            <option> ---- </option>
            <option value="school" onclick="document.getElementById('City').disabled=true;document.getElementById('school').disabled=false;">School</option>
            <option value="city" onClick="document.getElementById('school').disabled=true;document.getElementById('city').disabled=false;">City</option>
    </select>
    <select name="school" id="school">
        <option value="North Central MO College" selected="selected">North Central MO College</option>
    </select>
    <select name="city" id="city">
      <option value="Trenton" selected="selected" >Trenton</option>
  </select>

</form>

Code (markup):

 

To hide things, wrap them in divs with style display inline and when hiding, change inlink to none.

Peace,

 

thanks i used the div tags. the thought had never crossed my mind.
again thanks for the help

 

That is a javascript issue and php isn't going to hide a select box after you selected something unless they press the SUBMIT button and the server gets a chance to process the form. Otherwise i would stick with JavaScript and not php.