Left trims a string. Same as String.trim, but only for the beginning of a string.
@param {String} s The string to operate on.
@param {String} [what='\\s+'] What to trim.
@return {String} The left trimmed string
function ltrim (s, what) {
                    what = typeof what === 'string' ? what : '\\s+';
                    return s.replace(new RegExp('^' + what), '');
                }