Global Variables vs Local Variables (v28)

Revision 28 of this benchmark created by Honnza on

Description

This test compares the performance of global variables to local variables within functions.

Global variables should be slower because they do not exist in a function's activation object. JavaScript must traverse the Scope Chain to locate global variables.

Preparation HTML

<script>
  var a, b=0, res;
  function x() {
    for(a=0;a<200;a++)
      b+=a;
  }
function xy(c, d) {
    for(c=0;c<200;c++)
      d+=c;
    res = d;
  }
  function y() {
    var c,d=0;
    for(c=0;c<20;c++)
      d+=c;
    res = d;
  }
  function z(){
    var c = a,
        d = b;

    for(c=0;c<20;c++)
       d+=c;
    res = d;
  }
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
Global variables
x();
ready
Local variables
y();
ready
Cached global variables
z();
ready
Mixed
xy(a,b);
ready

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.