UPDATE: The Dynamics CRM in the Field blog just published a useful post on Script Errors after Installing UR12.

The next update to CRM 2011 introduces an expanded range of supported browsers.  You can learn more about the upcoming release here:

http://crm.dynamics.com/en-us/Polaris

http://crmpublish.blob.core.windows.net/docs/Release_Preview_Guide_December_2012_FINAL.pdf

Ahead of the release, the latest version of the CRM SDK has guidance on ensuring the JavaScript code you write works in the supported browsers:

http://msdn.microsoft.com/en-us/library/hh771584.aspx#BKMK_WriteJavaScriptForMutlipleBrowsers

The SDK also links to a blog post by the CRM team covering a tool to help existing customers identify where they might have cross browser compatibility issues in their existing web resources:

http://blogs.msdn.com/b/crm/archive/2012/06/21/microsoft-dynamics-crm-2011-custom-code-validation-tool-released.aspx

This tool is not guaranteed to find every cross browser compatibility issue.  As the blog post says, it is also possible for the tool to identify false positives.  Therefore, I would recommend that anyone planning on deploying this update test it in a non production environment first before applying it in production.

The good news is that if you have already followed the guidance in the CRM 2011 SDK regarding what’s supported in terms of customizations using web resources, then your customizations should continue to work after applying the update once it is released.  The CRM team has already done the work to validate that going through supported APIs works with the update.  The bad news is that sometimes people implement unsupported customizations, without understanding that what they’ve done is not supported.  Often times, they find a way to do something on a blog.  However, the blogger doesn’t make it clear that while the approach “works” it isn’t supported.  The resources above will help you identify and fix those kinds of issues in your code.  Please read these resources carefully, understand the potential impact to your customizations, and test appropriately.

I want to reiterate that the supplied resources will not guarantee you haven’t missed something.  They are not a replacement for testing.  They simply make it easier to identify and fix issues before you test.  Hence reducing the issues you find during testing.

@devkeydet