title: Set parameters on dropdown php
body: <p>I have 2 dropdown which are Court and Timeslot. I want it to be like this. When the 1st user select court A and select 8pm-9pm (1 hour slot) , then the 2nd user will not be able to see the items in the dropdown that the 1st user has selected. How should i do it? This is my codes:</p>
  
  <pre><code>&lt;select name="court" required&gt;
    &lt;option value=""&gt;Court&lt;/option&gt;
    &lt;option value="A"&gt;A&lt;/option&gt;
    &lt;option value="B"&gt;B&lt;/option&gt;
    &lt;option value="C"&gt;C&lt;/option&gt;
    &lt;option value="D"&gt;D&lt;/option&gt;
  &lt;/select&gt;
  
  
  &lt;select name="timeslot" required&gt;
    &lt;option value=""&gt;Time Slot&lt;/option&gt;
    &lt;option value="8.00 PM to 9.00 PM"&gt;8.00 PM to 9.00 PM (1 hour slot)&lt;/option&gt;
    &lt;option value="9.00 PM to 10.00 PM"&gt;9.00 PM to 10.00 PM (1 hour slot)&lt;/option&gt;
    &lt;option value="10.00 PM to 11.00 PM"&gt;10.00 PM to 11.00 PM (1 hour slot)&lt;/option&gt;
    &lt;option value="11.00 PM to 12.00 AM"&gt;11.00 PM to 12.00 AM (1 hour slot)&lt;/option&gt;
    &lt;option value="12.00 AM to 1.00 AM"&gt;12.00 AM to 1.00 AM (1 hour slot)&lt;/option&gt;
    &lt;option value="1.00 AM to 2.00 AM"&gt;1.00 AM to 2.00 AM (1 hour slot)&lt;/option&gt;
    &lt;option value="8.00 PM to 10.00 PM"&gt;8.00 PM to 10.00 PM (2 hours slot)&lt;/option&gt;
    &lt;option value="10.00 PM to 12.00 PM"&gt;10.00 PM to 12.00 AM (2 hours slot)&lt;/option&gt;
    &lt;option value="12.00 PM to 2.00 PM"&gt;12.00 AM to 2.00 AM (2 hours slot)&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>