I have a line of code that gets the following error when run through JSLint:
Lint at line 604 character 48: Insecure \'^\'. numExp = parseInt(val[1].replace(
All it's trying to tell you is that it's generally better to specify what can be entered instead of what can't.
In this case, your regex is actually stripping out bad characters, so it's safe to ignore the warning.