常用 JS 方法整理

1.截取指定字节数的字符串

/**
 * 截取指定字节的字符串
 * @param str 要截取的字符穿
 * @param len 要截取的长度，根据字节计算
 * @param suffix 截取前len个后，其余的字符的替换字符，一般用“…”
 * @returns {*}
 */
function cutString(str, len, suffix) {
  if (!str) return "";
  if (len <= 0) return "";
  if (!suffix) suffix = "";
  var templen = 0;
  for (var i = 0; i < str.length; i++) {
    if (str.charCodeAt(i) > 255) {
      templen += 2;
    } else {
      templen++
    }
    if (templen == len) {
      return str.substring(0, i + 1) + suffix;
    } else if (templen > len) {
      return str.substring(0, i) + suffix;
    }
  }
  return str;
}

2.判断是否微信

/**
 * 判断微信浏览器
 * @returns {Boolean}
 */
function isWeiXin() {
  var ua = window.navigator.userAgent.toLowerCase();
  if (ua.match(/MicroMessenger/i) == 'micromessenger') {
    return true;
  } else {
    return false;
  }
}

3.获取时间格式的几个举例

function getTimeFormat(time) {
  var date = new Date(parseInt(time) * 1000);
  var month, day, hour, min;
  parseInt(date.getMonth()) + 1 < 10 ? month = '0' + (parseInt(date.getMonth()) + 1) : month = parseInt(date.getMonth()) + 1;
  date.getDate() < 10 ? day = '0' + date.getDate() : day = date.getDate();
  date.getHours() < 10 ? hour = '0' + date.getHours() : hour = date.getHours();
  date.getMinutes() < 10 ? min = '0' + date.getMinutes() : min = date.getMinutes();
  return [month, day].join('-') + '  ' + hour + ':' + min
}

function getTimeFormatYMD(time) {
  var date = new Date(parseInt(time) * 1000);
  var year, month, day;
  year = date.getFullYear();
  parseInt(date.getMonth()) + 1 < 10 ? month = '0' + (parseInt(date.getMonth()) + 1) : month = parseInt(date.getMonth()) + 1;
  date.getDate() < 10 ? day = '0' + date.getDate() : day = date.getDate();
  return [year, month, day].join('-')
}

function getTimeFormatAll(time) {
  var date = new Date(parseInt(time) * 1000);
  var year, month, day, hour, min, second;
  year = date.getFullYear();
  parseInt(date.getMonth()) + 1 < 10 ? month = '0' + (parseInt(date.getMonth()) + 1) : month = parseInt(date.getMonth()) + 1;
  date.getDate() < 10 ? day = '0' + date.getDate() : day = date.getDate();
  date.getHours() < 10 ? hour = '0' + date.getHours() : hour = date.getHours();
  date.getMinutes() < 10 ? min = '0' + date.getMinutes() : min = date.getMinutes();
  date.getSeconds() < 10 ? second = '0' + date.getSeconds() : second = date.getSeconds();

  return [year, month, day].join('-') + '  ' + hour + ':' + min + ':' + second
}

4.获取字符串字节长度

JS中文网 – 前端进阶资源教程 www.javascriptC.com
一个致力于帮助开发者用代码改变世界为使命的平台，每天都可以在这里找到技术世界的头条内容

/**
 * 获取字符串字节长度 Js中文网 - 前端进阶资源分享(https://www.javascriptc.com/)
 * @param {String}
 * @returns {Boolean}
 */
function checkLength(v) {
  var realLength = 0;
  var len = v.length;
  for (var i = 0; i < len; i++) {
    var charCode = v.charCodeAt(i);
    if (charCode >= 0 && charCode <= 128) realLength += 1;
    else realLength += 2;
  }
  return realLength;
}

5.对象克隆、深拷贝

/**
 * 对象克隆&深拷贝
 * @param obj
 * @returns {{}}
 */
function cloneObj(obj) {
  var newO = {};
  if (obj instanceof Array) {
    newO = [];
  }
  for (var key in obj) {
    var val = obj[key];
    newO[key] = typeof val === 'object' ? arguments.callee(val) : val;
  }
  return newO;
};

克隆拷贝增强版

/**
 * 对象克隆&深拷贝
 * @param obj
 * @returns {{}}
 */
function clone(obj) {
  // Handle the 3 simple types, and null or undefined
  if (null == obj || "object" != typeof obj) return obj;
  // Handle Date
  if (obj instanceof Date) {
    var copy = new Date();
    copy.setTime(obj.getTime());
    return copy;
  }
  // Handle Array
  if (obj instanceof Array) {
    var copy = [];
    for (var i = 0,
    len = obj.length; i < len; ++i) {
      copy[i] = clone(obj[i]);
    }
    return copy;
  }
  // Handle Object
  if (obj instanceof Object) {
    var copy = {};
    for (attr in obj) {
      if (obj.hasOwnProperty(attr)) copy[attr] = clone(obj[attr]);
    }
    return copy;
  }
  throw new Error("Unable to copy obj! Its type isn't supported.");
}

测试用例：

var origin = {
  a: "text",
  b: null,
  c: undefined,
  e: {
    f: [1, 2]
  }
}

6.组织结构代码证验证

JS中文网 – 前端进阶资源教程 www.javascriptC.com
一个致力于帮助开发者用代码改变世界为使命的平台，每天都可以在这里找到技术世界的头条内容

验证规则：

组织机构代码是每一个机关、社会团体、企事业单位在全国范围内唯一的、始终不变的法定代码标识。最新使用的组织机构代码在1997年颁布实施，由8位数字（或大写拉丁字母）本体代码和1位数字（或大写拉丁字母）校验码组成。本体代码采用系列（即分区段）顺序编码方法。校验码按下列公式计算：8 C9 = 11 – MOD(∑Ci * Wi，11)… (2) i = 1其中：MOD——表示求余函数；i——表示代码字符从左到右位置序号；Ci——表示第i位置上的代码字符的值，采用附录A“代码字符集”所列字符；C9——表示校验码；Wi——表示第i位置上的加权因子，其数值如下表：i 1 2 3 4 5 6 7 8 Wi 3 7 9 10 5 8 4 2当MOD函数值为1（即C9 = 10）时，校验码用字母X表示。

验证方法：

checkOrgCodeValid: function(el) {
  var txtval = el.value;
  var values = txtval.split("-");
  var ws = [3, 7, 9, 10, 5, 8, 4, 2];
  var str = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
  var reg = /^([0-9A-Z]){8}$/;
  if (!reg.test(values[0])) {
    return false
  }
  var sum = 0;
  for (var i = 0; i < 8; i++) {
    sum += str.indexOf(values[0].charAt(i)) * ws[i];
  }
  var C9 = 11 - (sum % 11);
  var YC9 = values[1] + '';
  if (C9 == 11) {
    C9 = '0';// Js中文网 - 前端进阶资源分享(https://www.javascriptc.com/)
  } else if (C9 == 10) {
    C9 = 'X';
  } else {
    C9 = C9 + '';
  }
  return YC9 == C9;
}

7.身份证号验证

/**
 * 验证身份证号
 * @param el 号码输入input
 * @returns {boolean}
 */
function checkCardNo(el) {
  var txtval = el.value;
  var reg = /(^\d{15}$)|(^\d{18}$)|(^\d{17}(\d|X|x)$)/;
  return reg.test(txtval)
}

8.js正则为url添加http标识

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="renderer" content="webkit">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
  <title></title>
  <script>
        var html = 'http:/ / www.google.com ';
        html += '\rwww.google.com ';
        html += '\rcode.google.com ';
        html += '\rhttp: //code.google.com/hosting/search?q=label%3aPython';
        var regex = /(https?:\/\/)?(\w+\.?)+(\/[a-zA-Z0-9\?%=_\-\+\/]+)?/gi;
        alert('before replace:');
        alert(html);
        html = html.replace(regex,
            function(match, capture) {
                if (capture) {
                    return match
                } else {
                    return 'http://' + match;
                }
            });
        alert('after replace:');
        alert(html);
    </script>
</head>
<body>
</body>
</html>

9.URL有效性校验方法

JS中文网 – 前端进阶资源教程 www.javascriptC.com
一个致力于帮助开发者用代码改变世界为使命的平台，每天都可以在这里找到技术世界的头条内容

/**
 * URL有效性校验
 * @param str_url
 * @returns {boolean}
 */
function isURL(str_url) {
  // 验证url
  var strRegex = "^((https|http|ftp|rtsp|mms)?://)" + "?(([0-9a-z_!~*'().&=+$%-]+: )?[0-9a-z_!~*'().&=+$%-]+@)?" //
  ftp的user@ + "(([0-9]{1,3}\.){3}[0-9]{1,3}" // IP形式的URL- 199.194.52.184
  + "|" // 允许IP和DOMAIN（域名）
  + "([0-9a-z_!~*'()-]+\.)*" // 域名- www.
  + "([0-9a-z][0-9a-z-]{0,61})?[0-9a-z]\." // 二级域名
  + "[a-z]{2,6})" // first level domain- .com or .museum
  + "(:[0-9]{1,4})?" // 端口- :80
  + "((/?)|" // a slash isn't required if there is no file name
  + "(/[0-9a-z_!~*'().;?:@&=+$,%#-]+)+/?)$";
  var re = new RegExp(strRegex);
  return re.test(str_url);
}
// 建议的正则
functionisURL(str) {
  return !! str.match(/(((^https?:(?:\/\/)?)(?:[-;:&=\+\$,\w]+@)?[A-Za-z0-9.-]+|(?:www.|[-;:&=\+\$,\w]+@)[A-Za-z0-9.-]+)((?:\/[\+~%\/.\w-_]*)?\??(?:[-\+=&;%@.\w_]*)#?(?:[\w]*))?)$/g);
}

10.自定义jsonp方法

/**
 * 自定义封装jsonp方法
 * @param options
 */
jsonp = function(options) {
  options = options || {};
  if (!options.url || !options.callback) {
    throw new Error("参数不合法");
  }
  //创建 script 标签并加入到页面中
  var callbackName = ('jsonp_' + Math.random()).replace(".", "");
  var oHead = document.getElementsByTagName('head')[0];
  options.data[options.callback] = callbackName;
  var params = formatParams(options.data);
  var oS = document.createElement('script');
  oHead.appendChild(oS);
  //创建jsonp回调函数
  window[callbackName] = function(json) {
    oHead.removeChild(oS);
    clearTimeout(oS.timer);
    window[callbackName] = null;
    options.success && options.success(json);
  };
  //发送请求
  oS.src = options.url + '?' + params;
  //超时处理
  if (options.time) {
    oS.timer = setTimeout(function() {
      window[callbackName] = null;
      oHead.removeChild(oS);
      options.fail && options.fail({
        message: "超时"
      });
    },
    time);
  }
};
/**
 * 格式化参数
 * @param data
 * @returns {string}
 */
formatParams = function(data) {
  var arr = [];
  for (var name in data) {
    arr.push(encodeURIComponent(name) + '=' + encodeURIComponent(data[name]));
  }
  return arr.join('&');
}

11.cookie操作

//写cookies
setCookie = function(name, value, time) {
  var strsec = getsec(time);
  var exp = new Date();
  exp.setTime(exp.getTime() + strsec * 1);
  document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString();
}
//cookie操作辅助函数
getsec = function(str) {
  var str1 = str.substring(1, str.length) * 1;
  var str2 = str.substring(0, 1);
  if (str2 == "s") {
    return str1 * 1000;
  } else if (str2 == "h") {
    return str1 * 60 * 60 * 1000;
  } else if (str2 == "d") {
    return str1 * 24 * 60 * 60 * 1000;
  }
}
//读取cookies
getCookie = function(name) {
  var arr, reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");
  if (arr = document.cookie.match(reg)) return (arr[2]);
  else return null;
}

//删除cookies
delCookie = function(name) {
  var exp = new Date();
  exp.setTime(exp.getTime() - 1);
  var cval = getCookie(name);
  if (cval != null) document.cookie = name + "=" + cval + ";expires=" + exp.toGMTString();
}

12.生成随机字符串 (可指定长度)

/**
 * 生成随机字符串(可指定长度)
 * @param len
 * @returns {string}
 */
randomString = function(len) {
  len = len || 8;
  var $chars = 'ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnprstwxyz2345678';
  /****默认去掉了容易混淆的字符oOLl,9gq,Vv,Uu,I1****/
  var maxPos = $chars.length;
  var pwd = '';
  for (var i = 0; i < len; i++) {
    pwd += $chars.charAt(Math.floor(Math.random() * maxPos));
  }
  return pwd;
}

13.浏览器判断

function parseUA() {
  var u = navigator.userAgent;
  var u2 = navigator.userAgent.toLowerCase();
  return { //移动终端浏览器版本信息
    trident: u.indexOf('Trident') > -1,
    //IE内核
    presto: u.indexOf('Presto') > -1,
    //opera内核
    webKit: u.indexOf('AppleWebKit') > -1,
    //苹果、谷歌内核
    gecko: u.indexOf('Gecko') > -1 && u.indexOf('KHTML') == -1,
    //火狐内核
    mobile: !!u.match(/AppleWebKit.*Mobile.*/),
    //是否为移动终端
    ios: !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/),
    //ios终端
    android: u.indexOf('Android') > -1 || u.indexOf('Linux') > -1,
    //android终端或uc浏览器
    iPhone: u.indexOf('iPhone') > -1,
    //是否为iPhone或者QQHD浏览器
    iPad: u.indexOf('iPad') > -1,
    //是否iPad
    webApp: u.indexOf('Safari') == -1,
    //是否web应该程序，没有头部与底部
    iosv: u.substr(u.indexOf('iPhone OS') + 9, 3),
    weixin: u2.match(/MicroMessenger/i) == "micromessenger",
    ali: u.indexOf('AliApp') > -1,
  };
}
var ua = parseUA();
if (!ua.mobile) {
  location.href = './pc.html';
}

14.Rem移动端适配

var rem = {
  baseRem: 40,
  // 基准字号，按照iphone6应该为20，此处扩大2倍，便于计算
  baseWidth: 750,
  // 基准尺寸宽，此处是按照ihpone6的尺寸
  rootEle: document.getElementsByTagName("html")[0],
  initHandle: function() {
    this.setRemHandle();
    this.resizeHandle();
  },
  setRemHandle: function() {
    var clientWidth = document.documentElement.clientWidth || document.body.clientWidth;
    this.rootEle.style.fontSize = clientWidth * this.baseRem / this.baseWidth + "px";
  },
  resizeHandle: function() {
    var that = this;
    window.addEventListener("resize",
    function() {
      setTimeout(function() {
        that.setRemHandle();
      },
      300);
    });
  }
};
rem.initHandle();

15.获取url后参数

function GetRequest() {
  var url = location.search; //获取url中"?"符后的字串
  var theRequest = new Object();
  if (url.indexOf("?") != -1) {
    var str = url.substr(1);
    strs = str.split("&");
    for (var i = 0; i < strs.length; i++) {
      theRequest[strs[i].split("=")[0]] = (strs[i].split("=")[1]);
    }
  }
  return theRequest;
}

16.动态加载JS

function loadScript(url, callback) {
  var script = document.createElement("script");
  script.type = "text/";
  if (typeof(callback) != "undefined") {
    if (script.readyState) {
      script.onreadystatechange = function() {
        if (script.readyState == "loaded" || script.readyState == "complete") {
          script.onreadystatechange = null;
          callback();
        }
      };
    } else {
      script.onload = function() {
        callback();
      };
    }
  }
  script.src = url;
  document.body.appendChild(script);
}

17.生成随机颜色值

function getRandomColor () {
  const rgb = []
  for (let i = 0 ; i < 3; ++i){
    let color = Math.floor(Math.random() * 256).toString(16)
    color = color.length == 1 ? '0' + color : color
    rgb.push(color)
  }
  return '#' + rgb.join('')
}

18.事件绑定与解绑

ElementClass.prototype.on = function (name, callback) {
    this.callbacks[name] = this.callbacks[name] || []
    this.callbacks[name].push(callback)
}

ElementClass.prototype.off = function (name, callback) {
    var callbacks = this.callbacks[name]
    if (callbacks && callbacks instanceof Array) {
        var index = callbacks.indexOf(callback)
        if (index !== -1) callbacks.splice(index, 1)
    }
}

ElementClass.prototype.trigger = function (name, params) {
    var callbacks = this.callbacks[name]
    if (callbacks && callbacks instanceof Array) {
        callbacks.forEach((cb) => {
            cb(params)
        })
    }
}

19.移动端音频播放

/**
  * 移动端H5播放音乐处理，兼容微信端
  * @param el 音乐Audio元素
  */
function playMusic(el) {
    var b = document.getElementById(el);

    var c = function c() {
        b.play();
        document.removeEventListener("touchstart", c, true);
    };

    b.play();
    document.addEventListener("WeixinJSBridgeReady", function () {
        c();
    }, false);
    document.addEventListener("YixinJSBridgeReady", function () {
        c();
    }, false);
    document.addEventListener("touchstart", c, true);
}

20.移动端视频适配

<video class="video1" webkit-playsinline="true" x-webkit-airplay="true" playsinline="true" x5-video-player-type="h5" x5-video-player-fullscreen="true"  preload="auto" poster="poster图片地址" src="视频地址"></video>

作者：
链接：https://juejin.im/post/5b62d02ee51d453467552dc9