1:  <!-- STEP ONE: Copy this code into the BODY of your HTML document -->

   2:   

   3:  Enter a number in either field, then click outside the text box.

   4:   

   5:  <form>

   6:  F: 

   7:  <input type="text" name="F" value="32" 

   8:  onChange="C.value = 100/(212-32) * (this.value - 32 )"><br>

   9:  C: 

  10:  <input type="text" name="C" value="0" 

  11:  onChange="F.value = (212-32)/100 * this.value + 32 "><br>

  12:  </form>