How to do a price calculator

[jazco]

I am trying to create a price calculator that automatically calculates the price of custom made picture frame. I got an equation that finds the square area of the frame by multiplying the perimeter (2*length*width) by the thickness (which the user can choose from 1.5", 2" or 3"). Then it multiplies it by a decimal number (0.27 if the frame is 1.5" thick, 0.23 if its 2" thick, and 0.18 if its 3" thick). Then it adds a $5 custom made fee to the final answer. But when I save it to an html file and load it in Internet Explorer, it doesn't calculate. Do you guys have an idea how to make it work?

<SCRIPT LANGUAGE="JavaScript">
function calculate_total(){
var length = Number(document.
getElementById('calc').
length.value);
var width = Number(document.
getElementById('calc').
width.value);
var frame = Number(document.
getElementById('calc').
frame.options
[document.getElementById('calc...
frame.options.
selectedIndex].value);
var total = (2 * (length + width)) * frame;
switch (frame){
case 1.5:
total = total * 0.27;
break;
case 2:
total = total * 0.23;
break;
case 3:
total = total * 0.18;
break;
}

document.getElementById('calc'... = total + 5;
}
</script>

Sorry the cut off code so you might have to concatenate some lines above this if you have questions let me know.
And here is the form I used, again its very basic but it works.

<form name="calc" id="calc">
Length: <input type="text" name="length" onchange="calculate_total()" /><br />
Width: <input type="text" name="width" onchange="calculate_total()" /><br />
<select name="frame" onchange="calculate_total()">
<option value="0" selected>Select a Frame</option>
<option value="1.5">1.5" Narrow Barnwood</option>
<option value="2">2" Rustic Barnwood</option>
<option value="3">3" Thick Barnwood</option>
</select>
<br />
<br />
Total: <input id="total" name="total"/>
</form>

[Taltos]

I took a quick look and I don't see anything that stand out as an immediate problem. One thing I have seen is using the DOM calls directly in a calculation seems to be quirky. Sometimes it works and sometimes it doesn't. I usually do:

var formdata = document.getElementById('calc');
var length = document.formdata.length.value;
length = Number(length);

It makes for longer code but seems to be more stable and makes troubleshooting easier. You can output to an alert any point of your data manipulation to see what is going on.

Do you get any errors or it just never calculates?