<JavaScriptFuncation> in <RibbonDiffXml> not working
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I created a custom button in the ribbon menua bar in CRM 2011 and now I want to call a webresource js.  This is what I have now:

< Actions>
              < JavaScriptFunction FunctionName="functionName" Library="$webresource:opportunity_ribbon.js" />
< /Actions>

But when I click the button, no response at all.  Any idea what's wrong?  Thanks for all replies.