Floating point numbers in any language are inaccurate, if you're performing say, financial calculations then you can use fixed point numbers by using scaled integers. For example:
var SCALE = 100; // 0.01
var a = 0+1 * SCALE; // e.g. 2.5 would be 2+5 * SCALE
var b = 0+2 * SCALE;
if (a + b == 0+3 * SCALE) {
// this will work...
}
console.log(a / SCALE);