After developing our application and testing it against newer versions of the browsers, we are now realising that some of our customers are tied to IE8 still.
IE8 is on Vaadin’s list of supported browsers, but my initial tests are not promising.
Our users report that they frequently get “Stop running this script” dialogs
When I run IE8 in a VM the UI renders horribly slow; Fetching & displaying a table that takes 1-2 sek in Chrome, takes 30 sec or more in IE.
Before I dig deeper I would like to hear what I realistically can expect.
Currently we are running with 7.3.0.rc1 and the Valo theme.
I’m testing with IE8.0.7601 in a Win7 VM downloaded from modern.ie.
Our customers should be running the same IE version, but we don’t seem to get the same errors.
IE8 is much slower a browser than the modern ones in many ways, not only in rendering and simple JavaScript execution but also in handling reflows/context switches etc. Thus, while IE8 should work with Vaadin 7, you shouldn’t expect it to be anywhere near the performance of e.g. Chrome.
That said, 30s is very slow. Layouts and/or large tables are probably responsible at least for a significant fraction of that. See for instance the wiki article
Optimizing Sluggish UI and the comments to it - especially the use of CssLayout can help in many cases.
The “slow script” warning in IE8 is shown whenever a certain number of JS statements have been executed and is not related to the “clock time” spent. The same advice as above also applies to this.