Try this:
Open IE | Tools | Internet Options | Advanced tab |
CHECK:
Disable script debugging
[Specifies whether you want to turn off your script debugger, if one is
installed. Script debuggers are used by Web site developers to test programs
and scripts on their Web pages.]
UNCheck:
Display a notification about every script error
[Specifies whether to display the actual script errors when a page does not
appear properly due to problems with its scripting. This feature is off by
default, but is useful to developers when testing Web pages.]
Apply | OK