Trim string in JavaScript?

  1. Home
  2. javascript
  3. Trim string in JavaScript?

How do I trim a string in JavaScript?

First answer

All browsers since IE9+ have trim().

For those browsers who does not support trim(), you can use this polyfill from MDN:

if (!String.prototype.trim) {
    (function() {
        // Make sure we trim BOM and NBSP
        var rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g;
        String.prototype.trim = function() {
            return this.replace(rtrim, '');
        };
    })();
}

See this:

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

String.prototype.ltrim=function(){return this.replace(/^\s+/,'');};

String.prototype.rtrim=function(){return this.replace(/\s+$/,'');};

String.prototype.fulltrim=function(){return this.replace(/(?:(?:^|\n)\s+|\s+(?:$|\n))/g,'').replace(/\s+/g,' ');};

Second answer

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/

Third answer

There are a lot of implementations that can be used. The most obvious seems to be something like this:

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

" foo bar ".trim();  // "foo bar"
Reprint:https://stackoverflow.com/questions/498970/trim-string-in-javascript
Spread the love

Related articles

Comments are closed.