localStorage polyfill with check first

localstorage.polyfillcheck.js

(function(){
  if(
    !(function(t){
      try {
        window.localStorage.setItem(t,t);
        window.localStorage.removeItem(t);
        return true;
      } catch(e) {
        return false;
      }
    })('t')) {
    window.localStorage = {
      getItem: function (sKey) {
        if (!sKey || !this.hasOwnProperty(sKey)) { return null; }
        return unescape(document.cookie.replace(new RegExp("(?:^|.*;\\s*)" + escape(sKey).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=\\s*((?:[^;](?!;))*[^;]?).*"), "$1"));
      },
      key: function (nKeyId) {
        return unescape(document.cookie.replace(/\s*\=(?:.(?!;))*$/, "").split(/\s*\=(?:[^;](?!;))*[^;]?;\s*/)[nKeyId]);
      },
      setItem: function (sKey, sValue) {
        if(!sKey) { return; }
        document.cookie = escape(sKey) + "=" + escape(sValue) + "; expires=Tue, 19 Jan 2038 03:14:07 GMT; path=/";
        this.length = document.cookie.match(/\=/g).length;
      },
      length: 0,
      removeItem: function (sKey) {
        if (!sKey || !this.hasOwnProperty(sKey)) { return; }
        document.cookie = escape(sKey) + "=; expires=Thu, 01 Jan 1970 00:00:00 GMT; path=/";
        this.length--;
      },
      hasOwnProperty: function (sKey) {
        return (new RegExp("(?:^|;\\s*)" + escape(sKey).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=")).test(document.cookie);
      }
    };
    window.localStorage.length = (document.cookie.match(/\=/g) || window.localStorage).length;
  }
})();

min.js

(function(){try{window.localStorage.setItem("t","t");window.localStorage.removeItem("t");var b=!0}catch(a){b=!1}b||(window.localStorage={getItem:function(a){return a&&this.hasOwnProperty(a)?unescape(document.cookie.replace(new RegExp("(?:^|.*;\\s*)"+escape(a).replace(/[\-\.\+\*]/g,"\\$&")+"\\s*\\=\\s*((?:[^;](?!;))*[^;]?).*"),"$1")):null},key:function(a){return unescape(document.cookie.replace(/\s*=(?:.(?!;))*$/,"").split(/\s*=(?:[^;](?!;))*[^;]?;\s*/)[a])},setItem:function(a,b){a&&(document.cookie=
escape(a)+"="+escape(b)+"; expires=Tue, 19 Jan 2038 03:14:07 GMT; path=/",this.length=document.cookie.match(/=/g).length)},length:0,removeItem:function(a){a&&this.hasOwnProperty(a)&&(document.cookie=escape(a)+"=; expires=Thu, 01 Jan 1970 00:00:00 GMT; path=/",this.length--)},hasOwnProperty:function(a){return(new RegExp("(?:^|;\\s*)"+escape(a).replace(/[\-\.\+\*]/g,"\\$&")+"\\s*\\=")).test(document.cookie)}},window.localStorage.length=(document.cookie.match(/=/g)||window.localStorage).length)})();