Very slow kendo.support.scrollbar()

[Rowan]

Hello,

kendo.support.scrollbar() does a bunch of root node DOM manipulation behind the scenes, triggering a reflow of the entire page every time it is queried. This is despite the fact that all it does is return a fixed numeric value.

Is there any reason it needs to do the DOM manipulation every call? We have patched it as below, and a bunch of our code (including kendo elements!) now perform better.

var browserScrollbarWidth = kendo.support.scrollbar();
kendo.support.scrollbar = function () {
    return browserScrollbarWidth;
};

[Kiril Nikolov]

Hello Rowan,

Thank you for bringing this to our attention.

In your case you are not calculating width every time you call .scrollbar(), but you use the already calculated value, which is a good optimization. The need of calculating it every time is due to old browser support that change the scrollbar width in some specific scenarios. However if you do not aim to support those browsers and your solution works well, then I do not see a reason not to use it.

I have forwarded this to the person responsible for this functionality, so it will be considered for implementation if its no longer need.

Thanks again for bringing this up.

Regards,
Kiril Nikolov
Telerik