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Hi.

We have an application being developed using YUI2 which seems to perform very well in Chrome but quickly grinds to a halt using IE (we've used both versions 7 and 8 with similar results).

One area we've identified is the creation of TreeNode objects which seems to take a lot longer in IE (60s+ compared to sub-second in Chrome) - granted the numbers are large, around 3000, but these nodes are not visible initially and it simply seems to be creation of the objects that takes the bulk of the time. Even when we restrict the number of treenodes being created to around 100 the whole resposiveness of the UI still seems to suffer - such as using the scrollbar or reszing the window 'freezes' for several seconds before responding. In addition I find the application in IE feels sluggish in general so I suspect that the treenode is only one instance of a more common problem. Chrome doesn't appear to become sluggish with the same pages.

To my mind this sort of behaviour point to lots of event listeners being created and accessed during normal UI operations - for instance if we disable the display of tooltips then it does seem to improve the UI suggishness which might be because there are less mouseover events? However tooltips and 'drag and drop' are essential to the application - as is IE support.

Does anyone know if IE handles events significantly differently from Chrome or Firefox? Or does this sound like something else? We could look at migrating to using YUI3 and using delegate event handlers if that is likely to solve the problem, but it seems strange that there is such a vast difference between IE and other browsers and I'm wondering if we're just doing something silly? I'm at a loss as to how to investigate and diagnose this performance problem any further... any suggestions welcome.

Kind Regards,
Andy

Hi Satyam,

Thanks for the quick reply. You're right about the tooltips being added - they are implemented using the tooltip widget in YUI... Seeing how removing them made a noticable difference I guess the question is also what sort of overhead do they place on the browser when there are hundreds of them and are there any alternatives?

Cheers,
Andy