can anyone explain timeline view provided in webpage test? and sometimes visually complete is higher than fully loadedtime. is it correct and why is that so?
The timeline view is literally Chrome’s timeline from dev tools so any tutorials on that can be helpful. This is probably a good place to start: Chrome DevTools - Chrome Developers
As far as visually complete being later, yes - that can happen and can be normal. The load times are all based on network activity but things changing on the screen may not generate new requests on the network (and in the simplest case, it still takes some time to layout and render the content that did arrive on the network).
Thanks 
for your info really helpful to understand visually complete time
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And one more doubt if nothing displays within dom complete time can we refer visually complete time bcz it displays something in webpage to user