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

Use the Native JavaScript Methods: String.trimLeft(), String.trimRight(), and String.trim().

String.trim() is supported in IE9+ and all other major browsers:

'  Hello  '.trim()  //-> 'Hello'

String.trimLeft() and String.trimRight() are non-standard, but are supported in all major browsers except IE

'  Hello  '.trimLeft()   //-> 'Hello  '
'  Hello  '.trimRight()  //-> '  Hello'

IE support is easy with a polyfill however:

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