trim·

[Sunny]

正则写就可以

return str.replace(/(^\s+)|(\s+$)/g,'')//将前空格和后空格替换为空

[kangkang123269]

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

[beary]

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