js面试题 · 前端面试题精编（微信小程序（基础到高级）js视频资源、vue/js/html/css/React/ES6面试题、算法、插件大全）（轻松面对面试）（持续更新）

[1.简述同步和异步的区别](1.%E7%AE%80%E8%BF%B0%E5%90%8C%E6%AD%A5%E5%92%8C%E5%BC%82%E6%AD%A5%E7%9A%84%E5%8C%BA%E5%88%AB.md) [2.怎么添加、移除、复制、创建、和查找节点](2.%E6%80%8E%E4%B9%88%E6%B7%BB%E5%8A%A0%E3%80%81%E7%A7%BB%E9%99%A4%E3%80%81%E5%A4%8D%E5%88%B6%E3%80%81%E5%88%9B%E5%BB%BA%E3%80%81%E5%92%8C%E6%9F%A5%E6%89%BE%E8%8A%82%E7%82%B9.md) [3.实现一个函数clone 可以对Javascript中的五种主要数据类型（Number、string、Object、Array、Boolean）进行复制](3.%E5%AE%9E%E7%8E%B0%E4%B8%80%E4%B8%AA%E5%87%BD%E6%95%B0clone%E5%8F%AF%E4%BB%A5%E5%AF%B9Javascript%E4%B8%AD%E7%9A%84%E4%BA%94%E7%A7%8D%E4%B8%BB%E8%A6%81%E6%95%B0%E6%8D%AE%E7%B1%BB%E5%9E%8B%EF%BC%88Number%E3%80%81string%E3%80%81Object%E3%80%81Array%E3%80%81Boolean%EF%BC%89%E8%BF%9B%E8%A1%8C%E5%A4%8D%E5%88%B6.md) [4.如何消除一个数组里面重复的元素](4.%E5%A6%82%E4%BD%95%E6%B6%88%E9%99%A4%E4%B8%80%E4%B8%AA%E6%95%B0%E7%BB%84%E9%87%8C%E9%9D%A2%E9%87%8D%E5%A4%8D%E7%9A%84%E5%85%83%E7%B4%A0.md) [5.写一个返回闭包的函数](5.%E5%86%99%E4%B8%80%E4%B8%AA%E8%BF%94%E5%9B%9E%E9%97%AD%E5%8C%85%E7%9A%84%E5%87%BD%E6%95%B0.md) [6.使用递归完成1到100的累加](6.%E4%BD%BF%E7%94%A8%E9%80%92%E5%BD%92%E5%AE%8C%E6%88%901%E5%88%B0100%E7%9A%84%E7%B4%AF%E5%8A%A0.md) [7.Javascript有哪几种数据类型](7.Javascript%E6%9C%89%E5%93%AA%E5%87%A0%E7%A7%8D%E6%95%B0%E6%8D%AE%E7%B1%BB%E5%9E%8B.md) [8.如何判断数据类型](%E5%A6%82%E4%BD%95%E5%88%A4%E6%96%AD%E6%95%B0%E6%8D%AE%E7%B1%BB%E5%9E%8B.md) [9.console.log(1+'2')和console.log(1-'2')的打印结果](9.console.log1+2%E5%92%8Cconsole.log1-2%E7%9A%84%E6%89%93%E5%8D%B0%E7%BB%93%E6%9E%9C.md) [10.Js的事件委托是什么，原理是什么](10.Js%E7%9A%84%E4%BA%8B%E4%BB%B6%E5%A7%94%E6%89%98%E6%98%AF%E4%BB%80%E4%B9%88%EF%BC%8C%E5%8E%9F%E7%90%86%E6%98%AF%E4%BB%80%E4%B9%88.md) [11.如何改变函数内部的this指针的指向](11.%E5%A6%82%E4%BD%95%E6%94%B9%E5%8F%98%E5%87%BD%E6%95%B0%E5%86%85%E9%83%A8%E7%9A%84this%E6%8C%87%E9%92%88%E7%9A%84%E6%8C%87%E5%90%91.md) [12.列举几种解决跨域问题的方式，且说明原理](12.%E5%88%97%E4%B8%BE%E5%87%A0%E7%A7%8D%E8%A7%A3%E5%86%B3%E8%B7%A8%E5%9F%9F%E9%97%AE%E9%A2%98%E7%9A%84%E6%96%B9%E5%BC%8F%EF%BC%8C%E4%B8%94%E8%AF%B4%E6%98%8E%E5%8E%9F%E7%90%86.md) [13.谈谈垃圾回收机制的方式及内存管理](13.%E8%B0%88%E8%B0%88%E5%9E%83%E5%9C%BE%E5%9B%9E%E6%94%B6%E6%9C%BA%E5%88%B6%E7%9A%84%E6%96%B9%E5%BC%8F%E5%8F%8A%E5%86%85%E5%AD%98%E7%AE%A1%E7%90%86.md) [14.写一个function ，清除字符串前后的空格](14.%E5%86%99%E4%B8%80%E4%B8%AAfunction%EF%BC%8C%E6%B8%85%E9%99%A4%E5%AD%97%E7%AC%A6%E4%B8%B2%E5%89%8D%E5%90%8E%E7%9A%84%E7%A9%BA%E6%A0%BC.md) [15.js实现继承的方法有哪些](15.js%E5%AE%9E%E7%8E%B0%E7%BB%A7%E6%89%BF%E7%9A%84%E6%96%B9%E6%B3%95%E6%9C%89%E5%93%AA%E4%BA%9B.md) [16.判断一个变量是否是数组，有哪些办法](16.%E5%88%A4%E6%96%AD%E4%B8%80%E4%B8%AA%E5%8F%98%E9%87%8F%E6%98%AF%E5%90%A6%E6%98%AF%E6%95%B0%E7%BB%84%EF%BC%8C%E6%9C%89%E5%93%AA%E4%BA%9B%E5%8A%9E%E6%B3%95.md) [17.let ，const ，var 有什么区别](17.let%EF%BC%8Cconst%EF%BC%8Cvar%E6%9C%89%E4%BB%80%E4%B9%88%E5%8C%BA%E5%88%AB.md) [18.箭头函数与普通函数有什么区别](18.%E7%AE%AD%E5%A4%B4%E5%87%BD%E6%95%B0%E4%B8%8E%E6%99%AE%E9%80%9A%E5%87%BD%E6%95%B0%E6%9C%89%E4%BB%80%E4%B9%88%E5%8C%BA%E5%88%AB.md) [19.随机取1-10之间的整数](19.%E9%9A%8F%E6%9C%BA%E5%8F%961-10%E4%B9%8B%E9%97%B4%E7%9A%84%E6%95%B4%E6%95%B0.md) [20.new操作符具体干了什么](20.new%E6%93%8D%E4%BD%9C%E7%AC%A6%E5%85%B7%E4%BD%93%E5%B9%B2%E4%BA%86%E4%BB%80%E4%B9%88.md) [21.Ajax原理](21.Ajax%E5%8E%9F%E7%90%86.md) [22.模块化开发怎么做](22.%E6%A8%A1%E5%9D%97%E5%8C%96%E5%BC%80%E5%8F%91%E6%80%8E%E4%B9%88%E5%81%9A.md) [23.异步加载Js的方式有哪些](23.%E5%BC%82%E6%AD%A5%E5%8A%A0%E8%BD%BDJs%E7%9A%84%E6%96%B9%E5%BC%8F%E6%9C%89%E5%93%AA%E4%BA%9B.md) [24.xml和 json的区别](24.xml%E5%92%8Cjson%E7%9A%84%E5%8C%BA%E5%88%AB.md) [25.webpack如何实现打包的](25.webpack%E5%A6%82%E4%BD%95%E5%AE%9E%E7%8E%B0%E6%89%93%E5%8C%85%E7%9A%84.md) [26.常见web安全及防护原理](26.%E5%B8%B8%E8%A7%81web%E5%AE%89%E5%85%A8%E5%8F%8A%E9%98%B2%E6%8A%A4%E5%8E%9F%E7%90%86.md) [27.用过哪些设计模式](27.%E7%94%A8%E8%BF%87%E5%93%AA%E4%BA%9B%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F.md) [28.为什么要同源限制](28.%E4%B8%BA%E4%BB%80%E4%B9%88%E8%A6%81%E5%90%8C%E6%BA%90%E9%99%90%E5%88%B6.md) [29.offsetWidth/offsetHeight,clientWidth/clientHeight与scrollWidth/scrollHeight的区别](29.offsetWidth-offsetHeight,clientWidth-clientHeight%E4%B8%8EscrollWidth-scrollHeight%E7%9A%84%E5%8C%BA%E5%88%AB.md) [30.javascript有哪些方法定义对象](30.javascript%E6%9C%89%E5%93%AA%E4%BA%9B%E6%96%B9%E6%B3%95%E5%AE%9A%E4%B9%89%E5%AF%B9%E8%B1%A1.md) [31.说说你对promise的了解](31.%E8%AF%B4%E8%AF%B4%E4%BD%A0%E5%AF%B9promise%E7%9A%84%E4%BA%86%E8%A7%A3.md) [32.谈谈你对AMD、CMD的理解](32.%E8%B0%88%E8%B0%88%E4%BD%A0%E5%AF%B9AMD%E3%80%81CMD%E7%9A%84%E7%90%86%E8%A7%A3.md) [33.web开发中会话跟踪的方法有哪些](33.web%E5%BC%80%E5%8F%91%E4%B8%AD%E4%BC%9A%E8%AF%9D%E8%B7%9F%E8%B8%AA%E7%9A%84%E6%96%B9%E6%B3%95%E6%9C%89%E5%93%AA%E4%BA%9B.md) [34.介绍js有哪些内置对象？](34.%E4%BB%8B%E7%BB%8Djs%E6%9C%89%E5%93%AA%E4%BA%9B%E5%86%85%E7%BD%AE%E5%AF%B9%E8%B1%A1%EF%BC%9F.md) [35.说几条写JavaScript的基本规范？](35.%E8%AF%B4%E5%87%A0%E6%9D%A1%E5%86%99JavaScript%E7%9A%84%E5%9F%BA%E6%9C%AC%E8%A7%84%E8%8C%83%EF%BC%9F.md) [36.javascript创建对象的几种方式？](36.javascript%E5%88%9B%E5%BB%BA%E5%AF%B9%E8%B1%A1%E7%9A%84%E5%87%A0%E7%A7%8D%E6%96%B9%E5%BC%8F%EF%BC%9F.md) [37.eval是做什么的？](37.eval%E6%98%AF%E5%81%9A%E4%BB%80%E4%B9%88%E7%9A%84%EF%BC%9F.md) [38.null，undefined 的区别？](38.null%EF%BC%8Cundefined%E7%9A%84%E5%8C%BA%E5%88%AB%EF%BC%9F.md) [39.[“1”, “2”, “3”].map(parseInt) 答案是多少？](39.%5B%E2%80%9C1%E2%80%9D,%E2%80%9C2%E2%80%9D,%E2%80%9C3%E2%80%9D%5D.mapparseInt%E7%AD%94%E6%A1%88%E6%98%AF%E5%A4%9A%E5%B0%91%EF%BC%9F.md) [40.javascript 代码中的”use strict”;是什么意思 ? 使用它区别是什么？](40.javascript%E4%BB%A3%E7%A0%81%E4%B8%AD%E7%9A%84%E2%80%9Dusestrict%E2%80%9D;%E6%98%AF%E4%BB%80%E4%B9%88%E6%84%8F%E6%80%9D%E4%BD%BF%E7%94%A8%E5%AE%83%E5%8C%BA%E5%88%AB%E6%98%AF%E4%BB%80%E4%B9%88%EF%BC%9F.md) [41.js延迟加载的方式有哪些？](41.js%E5%BB%B6%E8%BF%9F%E5%8A%A0%E8%BD%BD%E7%9A%84%E6%96%B9%E5%BC%8F%E6%9C%89%E5%93%AA%E4%BA%9B%EF%BC%9F.md) [42.defer和async](42.defer%E5%92%8Casync.md) [43.说说严格模式的限制](43.%E8%AF%B4%E8%AF%B4%E4%B8%A5%E6%A0%BC%E6%A8%A1%E5%BC%8F%E7%9A%84%E9%99%90%E5%88%B6.md) [44.attribute和property的区别是什么？](44.attribute%E5%92%8Cproperty%E7%9A%84%E5%8C%BA%E5%88%AB%E6%98%AF%E4%BB%80%E4%B9%88%EF%BC%9F.md) [45.ECMAScript6 怎么写class么，为什么会出现class这种东西?](45.ECMAScript6%E6%80%8E%E4%B9%88%E5%86%99class%E4%B9%88%EF%BC%8C%E4%B8%BA%E4%BB%80%E4%B9%88%E4%BC%9A%E5%87%BA%E7%8E%B0class%E8%BF%99%E7%A7%8D%E4%B8%9C%E8%A5%BF.md) [46.常见兼容性问题](46.%E5%B8%B8%E8%A7%81%E5%85%BC%E5%AE%B9%E6%80%A7%E9%97%AE%E9%A2%98.md) [47.函数防抖节流的原理](47.%E5%87%BD%E6%95%B0%E9%98%B2%E6%8A%96%E8%8A%82%E6%B5%81%E7%9A%84%E5%8E%9F%E7%90%86.md) [48.原始类型有哪几种？null是对象吗？](48.%E5%8E%9F%E5%A7%8B%E7%B1%BB%E5%9E%8B%E6%9C%89%E5%93%AA%E5%87%A0%E7%A7%8D%EF%BC%9Fnull%E6%98%AF%E5%AF%B9%E8%B1%A1%E5%90%97%EF%BC%9F.md) [49.为什么console.log(0.2+0.1==0.3) //false](49.%E4%B8%BA%E4%BB%80%E4%B9%88console.log0.2+0.1==0.3--false.md) [50.说一下JS中类型转换的规则？](50.%E8%AF%B4%E4%B8%80%E4%B8%8BJS%E4%B8%AD%E7%B1%BB%E5%9E%8B%E8%BD%AC%E6%8D%A2%E7%9A%84%E8%A7%84%E5%88%99%EF%BC%9F.md) [51.深拷贝和浅拷贝的区别？如何实现](51.%E6%B7%B1%E6%8B%B7%E8%B4%9D%E5%92%8C%E6%B5%85%E6%8B%B7%E8%B4%9D%E7%9A%84%E5%8C%BA%E5%88%AB%EF%BC%9F%E5%A6%82%E4%BD%95%E5%AE%9E%E7%8E%B0.md) [52.如何判断this？箭头函数的this是什么](52.%E5%A6%82%E4%BD%95%E5%88%A4%E6%96%ADthis%EF%BC%9F%E7%AE%AD%E5%A4%B4%E5%87%BD%E6%95%B0%E7%9A%84this%E6%98%AF%E4%BB%80%E4%B9%88.md) [53.== 和 ===的区别](53.==%E5%92%8C===%E7%9A%84%E5%8C%BA%E5%88%AB.md) [54.什么是闭包](54.%E4%BB%80%E4%B9%88%E6%98%AF%E9%97%AD%E5%8C%85.md) [55.JavaScript原型，原型链 ? 有什么特点？](55.JavaScript%E5%8E%9F%E5%9E%8B%EF%BC%8C%E5%8E%9F%E5%9E%8B%E9%93%BE%E6%9C%89%E4%BB%80%E4%B9%88%E7%89%B9%E7%82%B9%EF%BC%9F.md) [56.typeof()和instanceof()的用法区别](56.typeof%E5%92%8Cinstanceof%E7%9A%84%E7%94%A8%E6%B3%95%E5%8C%BA%E5%88%AB.md) [57.什么是变量提升](57.%E4%BB%80%E4%B9%88%E6%98%AF%E5%8F%98%E9%87%8F%E6%8F%90%E5%8D%87.md) 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