Javascript regex - no white space at beginning + allow space in the middle

In your 2nd character class, \\s will match \ and s, and not \s. Thus it doesn't matches a whitespace. You should use just \s there. Also, move the hyphen towards the end, else it will create unintentional range in character class:

^[^-\s][a-zA-Z0-9_\s-]+$

You need to use this regex:

^[^-\s][\w\s-]+$

• Use start anchor ^
• No need to double escape \s
• Also important is to use hyphen as the first OR last character in the character class.
• \w is same as [a-zA-Z0-9_]