var num1 = 0.1;
var num2 = 0.2;
alert( parseFloat((num1 + num2).toFixed(2)) === 0.30 );
formatNum = function(f, digit) {
var m = Math.pow(10, digit);
return parseInt(f * m, 10) / m;
}
var num1 = 0.1;
var num2 = 0.2;
alert(Math.formatFloat(num1 + num2, 1) === 0.3)