ColdFusion 10 Error occurring only in IE9 - coldfusion

Question

My customer is encountering the error The 2 parameter of the Left function, which is now -1, must be a positive integer after migrating from ColdFusion 8 to ColdFusion 10. The page performs as expected in Firefox 31 and Chrome 36 on Windows 7. However, this error occurs in IE9 but not IE7. Are there different security settings in IE9 that prohibit the processing of the code?
The snippet of code in question is:
<!--- Populate the UserInfo struct --->
<cfloop INDEX="item" LIST="#COOKIE.MYELVIS_USERINFO#" DELIMITERS="&">
<cfset delim = #FindOneOf("=",item)#>
<cfif (len(item)-delim)>
<cfset UserInfo[UCase(left(item,delim-1))] = right(item,len(item)-delim)>
<cfelse>
<cfset UserInfo[UCase(left(item,delim-1))] = "">
</cfif>
</cfloop>
I'm torn to say it's a code error when it works in other browsers, just not IE9. Any thoughts? Thank you.

Answer 1

Perhaps have him clear cookies, he might have a holdover from cf 8 and perhaps the two versions encode differently. It looks like, if this is possible, one of the values doesn't contain a =.
Upon reviewing your code, I think this is what you need.
<cfloop INDEX="item" LIST="#COOKIE.MYELVIS_USERINFO#" DELIMITERS="&">
<cfset delim = #FindOneOf("=",item)#>
<cfif (delim) and (len(item)-delim)>
<cfset UserInfo[UCase(left(item,delim-1))] = right(item,len(item)-delim)>
<cfelse>
<cfset UserInfo[UCase(item)] = "">
</cfif>
</cfloop>