如果不支持 localStorage 则用 cookie 代替

//如果不支持 localStorage 则用 cookie 代替
//检测浏览器是否支持localStorage
if(typeof localStorage == 'undefined'){
//创建localStorage
var localStorageClass = function(){
  this.options = {
    expires : 60*24*3600,
    domain : "swe_ling@163.com"
  }
}

localStorageClass.prototype = {
  //初实化。添加过期时间
  init:function(){
  var date = new Date();
  date.setTime(date.getTime() + 60*24*3600);
  this.setItem('expires',date.toGMTString());
  },
  //内部函数参数说明(key) 检查key是否存在
  findItem:function(key){
  var bool = document.cookie.indexOf(key);
  if( bool < 0 ){
      return true;
  }else{
      return false;
  }
  },
       //得到元素值 获取元素值 若不存在则返回 null
  getItem:function(key){       
  var i = this.findItem(key);
  if(!i){
    var array = document.cookie.split(';')           
    for(var j=0;j < array.length;j++){
      var arraySplit = array[j];
      if(arraySplit.indexOf(key) > -1){
        var getValue = array[j].split('=');
        //将 getValue[0] trim删除两端空格
        getValue[0] = getValue[0].replace(/^\s\s*/, '').replace(/\s\s*$/, '')
        if(getValue[0]==key){
        return getValue[1];
        }else{
          return 'null';
        }
      }
    }
  }
  },
  //重新设置元素
  setItem:function(key,value){
    var i = this.findItem(key)
    document.cookie=key+'='+value;
  },
  //清除cookie 参数一个或多一
  clear:function(){
    for(var cl =0 ;cl < arguments.length;cl++){
      var date = new Date();
      date.setTime(date.getTime() - 100);
      document.cookie =arguments[cl] +"=a; expires=" + date.toGMTString();
    }
  }
}          
  var localStorage = new localStorageClass();
  localStorage.init();
}

localStorage.setItem('QQ1','562127378');
localStorage.setItem('QQ2','605003402');
document.write('QQ1: '+ localStorage.getItem('QQ2')+'<br />');
document.write('QQ2: '+localStorage.getItem('QQ1'));


//jQuery 的 cookie
jQuery.cookie = function(name, value, options) {
  if (typeof value != 'undefined') {
    options = options || {};
    if (value === null) {
      value = '';
      options = $.extend({}, options);
      options.expires = -1;
      }
      var expires = '';
      if (options.expires && (typeof options.expires == 'number' || options.expires.toUTCString)) {
        var date;
        if (typeof options.expires == 'number') {
        date = new Date();
        date.setTime(date.getTime() + (options.expires * 24 * 60 * 60 * 1000));
      } else {
        date = options.expires;
      }
        expires = '; expires=' + date.toUTCString();
      }
      var path = options.path ? '; path=' + (options.path) : '';
      var domain = options.domain ? '; domain=' + (options.domain) : '';
      var secure = options.secure ? '; secure' : '';
      document.cookie = [name, '=', encodeURIComponent(value), expires, path, domain, secure].join('');
      } else {
        var cookieValue = null;
        if (document.cookie && document.cookie != '') {
        var cookies = document.cookie.split(';');
        for (var i = 0; i < cookies.length; i++) {
        var cookie = jQuery.trim(cookies[i]);
        if (cookie.substring(0, name.length + 1) == (name + '=')) {
        cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
        break;
      }
      }
    }
    return cookieValue;
  }
};
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