//扩展实例1 字符串中首字符转大写 var test=' this is '; String.prototype.mytrim=function(){ var re=/^s+(.*?)s+$/; return this.replace(re,'$1'); }; console.log('['+test+']'); console.log('['+test.trim()+']'); //test.mytrim() 等价于:test.replace(re,'$1'); console.log('['+test.mytrim()+']'); name = 'aaa bbb ccc'; uw=name.replace(/w+/g, function(word){ console.log(word); return word.substring(0,1).toUpperCase()+word.substring(1);} );