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what factors reduced start rend time? - Printable Version

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what factors reduced start rend time? - Serena - 04-28-2012 01:00 PM

please see below test result:

start rent time:2.382s.

I think that JS may be influence start Render, is it right?
but I don't see which JS blocking start render time.

Do you tell me how to know which JS block? thank you!

RE: what factors reduced start rend time? - pmeenan - 05-01-2012 08:49 AM

Any JS at the top of the document will block start render (in the head or the beginning of the HTML). Additionally, JS that does a document.write before the browser renders will usually also block it.

You can do some a/b testing by using the blocking capabilities (advanced settings->block) and block the different js resources until you narrow it down (maybe start by blocking all js by using ".js").

Here's what it looks like when all js is blocked: http://www.webpagetest.org/result/120430_53_74ffe2c93d9f00b62d779394b6cc2e8a/