Javascript Regex - No White Space At Beginning + Allow Space in the Middle

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:


Regular expression for no white space at start or end, but allow white space in middle, empty and any 6-20 characters?

You can use this regex:


Working Demo

In a RegEx I need to allow spaces only in middle and prevent spaces at beginning and end

I assume it is used in some kind of a RegularExpressionAttribute validation, and you just want to use a single pattern for this.

You have already the first building block:


This matches any char but the ones defined in the set. It does not match whitespace. If you quantify with * and wrap with anchors, no whitespace will be allowed anywhere in the string. So, you just need to add an optional group (quantified with * or ? or {x,y} depending on how many spaces you want to allow):

^^^ ^^

If you want to also match an empty string, wrap the pattern with an optional non-capturing group:

^^^ ^^

Escape backslashes as needed.

As for the hyphen in the names: it might be appropriate to allow it in the same place as whitespace:


Regex that allows a single whitespace in the middle but with character limit.

You may use a positive lookahead here:


See the regex demo.


  • ^ - start of string
  • (?=.{3,30}$) - there can be 3 to 30 chars (other than linebreak, replace the . with [A-Za-z0-9\s] to be more specific)
  • [A-Za-z0-9]+ - 1+ alphanumeric chars
  • (?:\s[A-Za-z0-9]+)? - an optional (1 or 0) occurrences of a

    • \s - whitespace
    • [A-Za-z0-9]+ - 1+ alphanumeric symbols
  • $ - end of string.

Regex Expression to not allow spacing at beginning

Try the following regex


Explanation via Regex101. You can also test it there.

It matches the test cases you provided. Hope this helps!


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