Commented Unassigned: IE ModalPopupExtender Javascript Unhandled Exception [28000]

In build 15.1.4.0 ModalPopupExtender is causing an error in IE

Unhandled exception at line 1241, column 5 in http://localhost:81/ScriptResource.axd?....

0x800a1391 - JavaScript runtime error: 'console' is undefined

Code is:

Sys.Extended.Deprecated = function (oldMethodName, properMethodName) {
if (isUnminified && console && console.warn)
if(arguments.length == 1)
console.warn(oldMethodName + " is deprecated.");
else
console.warn(oldMethodName + " is deprecated. Use " + properMethodName + " instead.");
}

oldMethodName = set_OnOkScript(value)
properMethodName = set_onOkScript(value)


Comments: I have tried to reproduce the issue you are talking about but everything operates correctly on my side. Would you please provide a sample project showing the problem so that I can research it and find the cause?