calculating a total from a form

[peanuts]

Hi all ...

Let me first of all warn you I'm not really good a Javascript (jet) [img]images/smilies/xeye.gif[/img]

I want to calculate a total for a form and alert if some conditions aren't met ...

I'm going completely crazy here ... so any help would be appreciated.. here's the deal ..

there is 4 input's with name A - D their values need to be between 0 -50 and the total must be 50 exactly .....

this is what I got so far

function Optellen()
{
var total
total = 0
A = document.CQS.A.value
B = document.CQS.B.value
C = document.CQS.C.value
D = document.CQS.D.value

if(A = '' ) { A = 0 }
if(B = '' ) { B = 0 }
if(C = '' ) { C = 0 }
if(D = '' ) { D = 0 }

total += eval(A)
total += eval(B)
total += eval(C)
total += eval(D)

if (total > 50)
{
alert("The total can not be more than 50" )
}
else
{
document.CQS.total.value = total
}



} 

1 there must be an easier way .. two I keep getting NaN as an answer...

Please help

Edit:

I'm using the PHP code tag so I get nice outlined code but ofcourse it's javascript

[MikeFoster]

Use parseInt() instead of 'eval()'. And then use isNaN() before validating the values.

[peanuts]

Thanks I got it working now...