Alphanumeric dash and underscore but no spaces regular expression check JavaScript

Question

Trying to check input against a regular expression   The field should only allow alphanumeric characters  dashes and underscores and should NOT allow spaces   However  the code below allows spaces   What am I missing   var regexp      a-zA-Z0-9 -       var check    checkme   if  check search regexp     -1        alert  invalid      else       alert  valid

User · Answer

Try this    A-Za-z0-9 -      Should allow underscores and hyphens

User · Answer

try this one  it is working fine for me       a-zA-Z   a-zA-Z0-9-

User · Answer

However  the code below allows spaces    No  it doesn t   However  it will only match on input with a length of 1   For inputs with a length greater than or equal to 1  you need a   following the character class   var regexp      a-zA-Z0-9-       var check    checkme   if  check search regexp      -1        alert  invalid      else       alert  valid        Note that neither the -  in this instance  nor the   need escaping

User · Answer

This is the most concise syntax I could find for a regex expression to be used for this check  const regex       w-

User · Answer

You shouldn t use String match but RegExp prototype test  i e   abc  test  abcd    instead of String search   if you re only interested in a boolean value  You also need to repeat your character class as explained in the answer by Andy E   var regexp      a-zA-Z0-9-

User · Answer

Got stupid error  So post here  if anyone find it useful   -     - means hyphen  dot and underscore    -   - means all signs in range from dot to underscore

User · Answer

Don t escape the underscore  Might be causing some whackness

[javascript] Alphanumeric, dash and underscore but no spaces regular expression check JavaScript

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