Javascript calculations not transferring to paypal

[Megan Bade]

I am wondering if I may be missing something within my code to lead me to this question. Please forgive me as it has been a while since editing and developing web as I create more web design. I have a client who has created a web site with 1 product and the theory being the more you purchase the bigger the discount. I have created the java code for that but now I am having issue's with the calculations being transmitted to the paypal account. I am not sure where I have missed a step or what I can do to remedy the situation. I'm at my whits end as this has been a struggle.

Here is the code, thanks!!!

<script type="text/javascript">
var divsarray=new Array('div0','div1','div2');
 
function showDivs(divs)
{
//get number of div to show
var num = parseInt(divs);
 
//show the div
document.getElementById(divsarray[num]).style.display='block';
 
//add one for next div
document.getElementById('lastdiv').value=(num+1);
 
//set quantity field
var quantity = 'quantity' + num; 
 
//set price field
var price = 'price' + num;
 
//set total field
var total = 'total' + num;
 
//put values in inputs fields of div displayed above
document.getElementById(quantity).value= document.getElementById('quantity100').value;
document.getElementById(price).value = document.getElementById('price100').value;
document.getElementById(total).value=document.getElementById('total100').value;
 
//Clear the original input fields
document.getElementById('quantity100').value = "";
document.getElementById('mySelect').options[0].selected=true;
document.getElementById('price100').value = "";
document.getElementById('total100').value = "";
document.getElementById('grand').style.display='block';
 
//calculate the grand total
var grand=0;
for(var j=0;j<divsarray.length;j++)
{
var mytotal = "total" + j;
grand = eval(document.getElementById(mytotal).value) + grand;
document.getElementById('grandtotal').value=grand;
}
}
 
function updateForm(what) 
{
selected = what.mySelect.selectedIndex;
values = what.mySelect.options[selected].value;
document.getElementById('price100').value = values;
document.getElementById('total100').value = eval(values * document.getElementById('quantity100').value).toFixed(2);
}
</script>
<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
        <input type="hidden" name="cmd" value="_xclick" />
        <input type="hidden" name="upload" value="1" />
        <input type="hidden" name="business" value="[e-mail]" />
        <input type="hidden" name="currency_code" value="USD" />
        <input type="hidden" name="return" value="http://www.thingsofskill.com/success.html" />
 
        Quantity / Price per Unit / Total
        <div id="div0" style="display:none">
  <input type="text" name="quantity0" id="quantity0">
  <input type="text" name="price0" id="price0">
  <input type="text" name="total0" id="total0" value="0">
  <p>
  </div>
  <div id="div1" style="display:none">
  <input type="text" name="quantity1" id="quantity1">
  <input type="text" name="price1" id="price1">
  <input type="text" name="total1" id="total1" value="0">
  <p>
  </div>
  <div id="div2" style="display:none">
  <input type="text" name="quantity2" id="quantity2">
  <input type="text" name="price2" id="price2">
  <input type="text" name="total2" id="total2" value="0">
  <p>
  </div>
  <div id="grand" style="display:none">
    Order Total:<br>
  <input type="text" value="0" id="grandtotal" name="grandtotal">
  </div>
  <p>
  <input name="quantity100" type="text" id="quantity100" size="3">
  <select name="mySelect" onChange="updateForm(this.form)">
  <option value="">
  <option value="28.00">1
  <option value="24.99">2
  <option value="21.99">3
  </select>
  <input name="price100" type="text" id="price100" size="7">
  <input name="total100" type="text" id="total100" size="7">
   <input type="submit" value="PayPal" />
      </form>
      </td>
    </tr>
  </table>
</div>