====== Regex - Alpha-numeric and underscore ====== ===== Letters, underscore, numbers ===== ^\w+$ ---- ===== Letters, underscore, numbers (2-5 in length) ===== ^\w{2,5} ---- ===== Letters, underscore, numbers and Chinese characters ===== ^[\u4E00-\u9FA5A-Za-z0-9_]+$ ----
^\w+$
^\w{2,5}
^[\u4E00-\u9FA5A-Za-z0-9_]+$