摘要： 1.var a=null==undefined?1:"abc";var b=typeof(a);var c=typeof(b);var d=typeof(null);console.log(a);console.log(b);console.log(c);console.log(d);写出a,b,c,d结果值var a=null==undefined?1:"abc";//1var b=typeof(a);//numbervar c=typeof(b);//stringvar d=typeof(null);//object2.<script type 阅读全文