Hi:
I am writing a script for school and the script involves 3 dropdown lists of products. If a certain product is selected, say a "canon printer" then there would be no tax on this item but tax on the rest. What would be the best way to do this?

Here is some code:

HTML
<tr>
<td colspan=4>
<h3>Printers</h3>
</td>
</tr>

<tr>
<td>
<select name="s1" onChange="which_prt()">
<option value="none" selected></option>
<option value="99.01">Epson Stylus C88 </option>
<option value="38.05">Canon Pixma IP1600</option>
<option value="957.11">EPSON STYLUS PHOTO 2200</option>
</select>
</td>

<td>
<input type="text" name="prt_qty" onChange="totalup_prt()"/>
</td>

<td>
<input type="text" name="prt_price" disabled/>
</td>

<td>
<input type="text" name="prt_total" disabled/>
</td>

</tr>



Javascript
function which_prt()
{
for (i=0;i<document.form1.s1.length;i++)
    {
    if(document.form1.s1[i].selected==true)
        {
        if (document.form1.s1.value=="none")
            {
            document.form1.prt_qty.value=""
            document.form1.prt_price.value=""
            document.form1.prt_total.value=""
            tmp_prt_qty=0
            tmp_prt_price=0
            tmp_total_ord=(parseFloat(tmp_total_ord.toFixed(2) )-parseFloat(tmp_prt_total.toFixed(2)))
            tmp_prt_total=0
            total_invoice()
            }
        else
            {
            document.form1.prt_qty.value=""
            document.form1.prt_price.value=""
            document.form1.prt_total.value=""
            document.form1.prt_qty.disabled=false
            tmp_prt_price=document.form1.s1.value;
            document.form1.prt_price.value=("$"+tmp_prt_price)
            }
        }
    }


}

function totalup_prt()
{
document.form1.prt_qty.disabled=true
tmp_prt_qty=document.form1.prt_qty.value
tmp_prt_total=(tmp_prt_price*tmp_prt_qty)
document.form1.prt_total.value=("$"+tmp_prt_total. toFixed(2))
document.form1.prt_total.value=document.form1.prt_ total.value
total_invoice()
}

Combine the values of your other 2 dropdowns add the effective tax rate then add in the value of your none taxed items so something like:

function calculate{
var total;
var taxRate = 6.5;
var taxTotal;

total = (parseFloat(document.form1.selectbox1.options[document.form1.selectbox1.selectedIndex].value) + parseFloat(document.form1.selectbox2.options[document.form1.selectbox2.selectedIndex].value));

taxTotal = total * taxRate;
total = total + taxTotal;

total = total + parseFloat(document.form1.selectbox2.options[document.form1.selectbox2.selectedIndex].value);
}

Of course you will have to deal with NaN values and such but that is how I would do it (more or less)



-------------------------
I will only tell you how to do it, not do it for you.
Unless, of course, you want to hire me to do work for you.

^^Thats my signature