Pounds & Ounces Calculator

Hi,

Using JavaScript, how do I subtract a weight from a drop-down menu from another drop-down menu, to calculate the amount of weight loss?
In total there should be 6 drop-down boxes, these are the following:

1: Pounds (Before), 2. Ounces (Before), 3. Fraction (Before), 4. Pounds (After), 5. Ounces (After), & 6. Fraction (After)

For example if:

Drop-Down Box 1 = 5
Drop-Down Box 2 = 3
Drop-Down Box 3 = ¾

Drop-Down Box 4 = 3
Drop-Down Box 5 = 2
Drop-Down Box 6 = ¼

Answer = 2.1½ have been lost.

 

well.. might need some code up to actually see what you're doing but..

i'm thinking you want to have this calculated each time a drop down menu is changed or something of the sort..

so if each option's value is the same as it's text we can do something like this..

<select id="lb1">
  <option value="5" onchange="calculate(pounds);">5
  <option ...
  ...
</select>

<select id="lb2">
  <option value="5" onchange="calculate(pounds);">5
  <option ...
  ...
</select>

...

<p>
Pounds Lost: <span id="poundoutput"></span>
...
</p>

Code (markup):

and than the javascript

function calculate(weighttype)
{
  if (weighttype == pounds)
  {
     document.getElementById("poundoutput").text = document.getElementById("lb1").value - document.getElementById("lb2").value
  }
}

Code (markup):

i haven't tested any of this.. and their most likely is a better way to do it.. just thought i'd throw you a bone anyways.. good luck

 

I suspect seriously that this is an assignment question, in which case this isn't going to do you much good.