Bytes In Mismatch

[vmichnowicz]

Sometimes I notice a mismatch in the reported Bytes In at Document complete. When I add the "Bytes Downloaded" for each resource downloaded before document complete I expect the get the same number of KBs as listed in the Document Complete Bytes In column. However, sometimes this is not the case.

Take this test for example: http://www.webpagetest.org/result/140531...1/details/

The reported Bytes In at document complete is 557 KB. However, when I add the Bytes Downloaded for each resources downloaded before document complete I get ~471 KB.

Where are those ~86 KB coming from?

I am using the following JavaScript to add up all the number by the way:

Code:

var total = 0;
$('.reqBytes.oddRender, .reqBytes.evenRender, .reqBytes.oddDoc, .reqBytes.evenDoc,').each(function() {
    total += parseFloat( $(this).text() );
});
console.log(total);