Trim string in JavaScript?

Question

How do I trim a string in JavaScript? That is, how do I remove all whitespace from the beginning and the end of the string in JavaScript?

Answer 1

Although there are a bunch of correct answers above, it should be noted that the String object in JavaScript has a native .trim() method as of ECMAScript 5. Thus ideally any attempt to prototype the trim method should really check to see if it already exists first.

if(!String.prototype.trim){  
  String.prototype.trim = function(){  
    return this.replace(/^\s+|\s+$/g,'');  
  };  
}

Added natively in: JavaScript 1.8.1 / ECMAScript 5

Thus supported in:

Firefox: 3.5+

Safari: 5+

Internet Explorer: IE9+ (in Standards mode only!) http://blogs.msdn.com/b/ie/archive/2010/06/25/enhanced-scripting-in-ie9-ecmascript-5-support-and-more.aspx

Chrome: 5+

Opera: 10.5+

ECMAScript 5 Support Table: http://kangax.github.com/es5-compat-table/