XMLHttpRequest objects kept in memory?

Hi,

Could anyone tell me why the memory usage gets increased by almost 7MB when running that script:

for (var i=0; i < 10000; ++i) {
  new XMLHttpRequest();
}

(of course this is just a test to pinpoint my issue, not a code that would be usefull in any manner!)

There isn't any reference to those objects, I thought they wouldn't be kept in memory...

Note: to get the numbers I look at the "Memory Report" on Xcode

Thanks