You attempted to create a character class for a regular expression match, but did not include the right bracket. Individual literal character combinations can be assembled into character classes by placing them within brackets. A character class matches any one character it contains. For example, /[abc]/ matches any one of the letters "a", "b", or "c".
To correct this error
Add the right bracket to the regular expression.
Note If you want to match a single bracket, escape it with a backslash - \[ - so it is not interpreted as a special character by JScript.