declaring variable inside vs outside loop

JavaScript performance comparison

Revision 2 of this test case created

Preparation code

 
<script>
Benchmark.prototype.setup = function() {
    var items = [];
   
    for(var i = 0; i < 10000; i++) {
      items.push(i);
    }
};
</script>

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

Testing in unknown unknown
Test Ops/sec
inside
for(var i = 0; i < items.length; i++) {
  var item = items[i];
}
pending…
outside
var item;

for(var i = 0; i < items.length; i++) {
  item = items[i];
}
pending…
in1
var l = items.length;
for(var i = 0; i < l; i++) {
  var item = items[i];
}
pending…

Compare results of other browsers

Revisions

You can edit these tests or add even more tests to this page by appending /edit to the URL. Here’s a list of current revisions for this page:

0 comments

Add a comment