Trim string in JavaScript

How do I remove all whitespace from the start and end of the string?


  • 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, then $.trim(str) is always available, which handles undefined/null as well.

    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,' ');};