Returns size (length) of any type if possible

sizeof.js

function sizeof(o) {
  if (typeof(o) == "object") {
    if (o.length !== void 0) {
      return o.length;
    } else {
      var i = 0;
      for (var k in o) i++;
      return i;
    }
  } else if (typeof(o) == "string") {
    return o.length;
  } else {
    return 1;
  }
}