https://segmentfault.com/a/1190000015383749
1.
console.log(typeof []) //"object" console.log(typeof typeof []) //=》typeof "object" //"string"
因为typeof返回结果都是字符串
2.
<script type="text/javascript"> var num = parseInt('35.5px'); if (num == 35.5) { alert(0) } else if (num == 35) { alert(1) } else if (num == NaN) { alert(2) } else if (typeof num == 'number') { alert(3) } else { alert(4) } console.log(typeof num)//number console.log(typeof num == 'number')//true //3 </script>