摘要：全局域变量在局部可见，局部变量在全局不可见var global_value = 'global value'; func();console.log(local_value);function func(){ var local_value = 'local_value'; console.log(global_value);}输出：1.global value2.Uncaught ReferenceError: local_value is not definedanonymous function所以，局部域可以修改全局域变量的值var global_val 阅读全文