RegEx for no whitespace at the beginning and end

Question

I want to design an expression for not allowing whitespace at the beginning and at the end of a string, but allowing in the middle of the string.

The regex I\'ve tri

Answer 1

Other answers introduce a limit on the length of the match. This can be avoided using Negative lookaheads and lookbehinds:

^(?!\s)([a-zA-Z0-9\s])*?(?

This starts by checking that the first character is not whitespace ^(?!\s). It then captures the characters you want a-zA-Z0-9\s non greedily (*?), and ends by checking that the character before $ (end of string/line) is not \s.

Check that lookaheads/lookbehinds are supported in your platform/browser.