Trim string in JavaScript

All browsers since IE9+ have trim() method for strings:

" \n test \n ".trim(); // returns "test" here

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, '');
        };
    })();
}

That said, if using jQuery, $.trim(str) is also available and handles undefined/null.

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,' ');};

The trim from jQuery is convenient if you are already using that framework.

$.trim('  your string   ');

I tend to use jQuery often, so trimming strings with it is natural for me. But it's possible that there is backlash against jQuery out there? :)

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"

Simple version here What is a general function for JavaScript trim?

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