unterminated regular expression literal js error

Regular expression literals should be surrounded by the delimiters(/). There's no terminating delimiter:

/^(https?|ftp):\/\//i
//                 ^

---

For example:

>> /^(https?|ftp):\/\//i.test('http://stackoverflow.com/')
true
>> /^(https?|ftp):\/\//i.test('telnet://stackoverflow.com/')
false

You can also get this error if you're simply attempting to concatenate a variable that utilizes a regular expression and forget a quotation mark somewhere.