5calc is a project mainly written in JAVASCRIPT and C++, it's free.
HTML5 based calculator
5calc is an HTML5-based calculator with built-in theming abilities.
https://chrome.google.com/webstore/detail/jcbncbadgbbcfnlfmhjbndifohmeckib/
5calc has been tested and is working in Firefox 3.6+, Chrome 8+, and Opera 11+, although it will probably work in many other browsers.
No extra requirements as of yet.
+ ......... Add
- ......... Subtract
/ ......... Divide
* ......... Multiply
x ......... Multiply
= ......... Calculate
Enter ..... Calculate
Escape .... Clear
Backspace . Backspace
Delete .... Backspace
( ......... Left paren
) ......... Right paren
. ......... Decimal
0 ......... Zero
1 ......... One
2 ......... Two
3 ......... Three
4 ......... Four
5 ......... Five
6 ......... Six
7 ......... Seven
8 ......... Eight
9 ......... Nine
s ......... Sine
S ......... Arcsine
c ......... Cosine
C ......... Arccosine
t ......... Tangent
T ......... Arctangent
| ......... Pipe (absolute value)
l ......... Log (base 10)
n ......... Natural log (base E)
! ......... Factorial
r ......... Square root == x^(1/2)
% ......... Modulo (remainder)
^ ......... Exponent
p ......... Pi
e ......... E