Adding Numbers, long decimal number

[barkster]

I'm trying to add simple numbers together from two fields on a form to update the cart total when the user changes their shipping selection.  When it adds the numbers 8.95 + 4.95 it gives me 13.549999999999999, why is that.  I've tried changing my function several different ways with no result.  Also, if I have a number with a comma do I need to strip out the comma somehow first.

 

function updatetotal() {
var total = document.getElementById('total').value - 0;
var selObj = document.getElementById('shipcost');
var selIndex = selObj.selectedIndex;	
var shipping = selObj.options[selIndex].value- 0; 
var grandtotal = parseFloat(total + shipping);
document.getElementById('grandtotal').innerHTML = "<strong>Grand Total: $"+grandtotal+"</strong>";	
}

 

also can't I simplify the line to get the selected value of the listbox?

[barkster]

Man, wish you could edit your posts....  I meant it is adding 8.95 + 4.60 = 13.54999999999999

[barkster]

Here is a javscript calculator and it does the same thing, why is this happening

 

http://javascript.internet.com/math-related/bettercalculator-1.2.html