Find Highest And Lowest Values Of Variables In Form Post

Hi All
Had a look around but cant figure out how to do this. I have a html form with each day of the week. Each day you can select the start and finish times of your day.

Each pulldown id is monStart, monFinish and so on. So when posted I have 14 variables. is there anyway I can pull out the lowest start time and highest finish time.

Code below and so on for each day… Any help or ideas would be great

<select name=“monStart” id=“monStart”>
<option value=“00” selected=“selected”>12am</option>
<option value=“1”>1am</option>
<option value=“2”>2am</option>
<option value=“3”>3am</option>
<option value=“4”>4am</option>
<option value=“5”>5am</option>
<option value=“6”>6am</option>
<option value=“7”>7am</option>
<option value=“8”>8am</option>
<option value=“9”>9am</option>
<option value=“10”>10am</option>
<option value=“11”>11am</option>
<option value=“12”>12am</option>
<option value=“13”>1pm</option>
<option value=“14”>2pm</option>
<option value=“15”>3pm</option>
<option value=“16”>4pm</option>
<option value=“17”>5pm</option>
<option value=“18”>6pm</option>
<option value=“19”>7pm</option>
<option value=“20”>8pm</option>
<option value=“21”>9pm</option>
<option value=“22”>10pm</option>
<option value=“23”>11pm</option>
<option value=“99”>Closed</option>

Figured it, put in array and use max and min