String strip for JavaScript

Question

What s a clean and efficient JavaScript implementation to strip leading and trailing spaces from a string    For example     dog    dog      dog                dog    all get turned into   dog

User · Answer

For jquery users  how about   trim s

User · Answer

If  rather than writing new code to trim a string  you re looking at existing code that calls  strip    and wondering why it isn t working  you might want to check whether it attempts to include something like the prototypejs framework  and make sure it s actually getting loaded  That framework adds a strip function to all String objects  but if e g  you upgraded it and your web pages are still referring to the old  js file it ll of course not work

User · Answer

Use this   if typeof String prototype trim       undefined         String prototype trim   function                  return String this  replace    s   s   g                  The trim function will now be available as a first-class function on your strings   For example     dog  trim        dog    true   EDIT  Took J-P s suggestion to combine the regex patterns into one   Also added the global modifier per Christoph s suggestion   Took Matthew Crumley s idea about sniffing on the trim function prior to recreating it   This is done in case the version of JavaScript used on the client is more recent and therefore has its own  native trim function

User · Answer

Steven Levithan once wrote about how to implement a Faster JavaScript Trim  It   s definitely worth a look

User · Answer

Gumbo already noted this in a comment  but this bears repeating as an answer  the trim   method was added in JavaScript 1 8 1 and is supported by all modern browsers  Firefox 3 5   IE 9  Chrome 10  Safari 5 x   although IE 8 and older do not support it   Usage is simple       foo n t    trim     gt   foo    See also    https   developer mozilla org en JavaScript Reference Global Objects String Trim http   msdn microsoft com en-us library windows apps ff679971 28v vs 94 29 aspx

User · Answer

Here s the function I use   function trim s      return   s         replace     s   s   g

User · Answer

A better polyfill from the MDN that supports removal of BOM and NBSP   if   String prototype trim      String prototype trim   function          return this replace     s uFEFF xA0     s uFEFF xA0    g                Bear in mind that modifying built-in prototypes comes with a performance hit  due to the JS engine bailing on a number of runtime optimizations   and in performance critical situations you may need to consider the alternative of defining myTrimFunction string  instead  That being said  if you are targeting an older environment without native  trim   support  you are likely to have more important performance issues to deal with

User · Answer

If you re already using jQuery  then you may want to have a look at jQuery trim   which is already provided with jQuery

[javascript] String strip() for JavaScript?

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