title: Efficiency of bitwise operation in Javascript
body: <p>According to <a href="http://www.w3schools.com/js/js_numbers.asp" rel="nofollow noreferrer">w3schools</a></p>
  <blockquote>
  <p>Unlike many other programming languages, JavaScript does not define different types of numbers, like integers, short, long, floating-point etc.</p>
  <p>JavaScript numbers are always stored as double precision floating point numbers, following the international IEEE 754 standard.</p>
  </blockquote>
  <p>So my question comes: if we want to perform a bitwise operation, how javascript translates that 64-bit IEEE 754 standard float to an ordinary 32-bit integer, and how efficient it is? From intuition, converting numbers will be costly, so will it still be more efficient to use bit shifting than multiply by 2<sup>n</sup>?</p>
  <p>Thank you very much!</p>