JS 判断类型

1、typeof运算符

  console.log("测试number:"+typeof 1);
  console.log("测试string:"+typeof "str");
  console.log("测试false:"+typeof false);
  console.log("测试null:"+typeof null);
  console.log("测试undefined:"+typeof undefined);
  console.log("测试Object:"+typeof new Object());
  console.log("测试Object:"+typeof new Array());
  console.log("看看typeof NaN是啥:"+typeof NaN);
  console.log("我想看看数组［1，2，3]类型:"+typeof [1,2,3]);
  console.log("看看function是啥:"+typeof function(){});

2、instanceof操作符（基于原型链）

  console.log("测试number:"+typeof 1);
  console.log("测试string:"+typeof "str");
  console.log("测试false:"+typeof false);
  console.log("测试null:"+typeof null);
  console.log("测试undefined:"+typeof undefined);
  console.log("测试Object:"+typeof new Object());
  console.log("测试Object:"+typeof new Array());
  console.log("看看typeof NaN是啥:"+typeof NaN);
  console.log("我想看看数组［1，2，3]类型:"+typeof [1,2,3]);
  console.log("看看function是啥:"+typeof function(){});

3、Object.prototype.toString方法