利用html5中的localStorage获取网页被访问的次数

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
    </head>
    <body>
        <div id="box"></div>
        <script type="text/javascript">
            function setStorage(){
                if(localStorage.counter){
                    localStorage.counter=Number(localStorage.counter)+1;
                }else{
                    localStorage.counter=1;
                }
                return localStorage.counter;
            }
            var counter=setStorage();
            var oBox=document.getElementById('box');
            oBox.innerHTML="该网页被访问的次数为"+counter+"次";            
        </script>
    </body>
</html>