<html>
<script>
function add(a,b){
var n = 0;
// var c = false;
var c = 0;
for( var i = 1; i != 0; i = i << 1) {
var _a = (a & 1 ) == 1;
var _b = (b & 1 ) == 1;
var _n = (_a ^ _b ) ^ c;
c = _a & (_b | c ) | ( _b & c );
n = n | (_n ? i : 0);
a = a >> 1;
b = b >> 1;
}
return n;
}
alert( add(21,32));
</script>
</html>
