web存储方法，现成代码

function setCookie(cname,cvalue,exdays){
    var d = new Date();
    d.setTime(d.getTime()+(exdays*24*60*60*1000));
    var expires = "expires="+d.toGMTString();
    document.cookie = cname+"="+cvalue+"; "+expires;
}
function getCookie(cname){
    var name = cname + "=";
    var ca = document.cookie.split(‘;‘);
    for(var i=0; i<ca.length; i++) {
        var c = ca[i].trim();
        if (c.indexOf(name)==0) { return c.substring(name.length,c.length); }
    }
    return "";
}
function checkCookie(){
    var user=getCookie("username");
    if (user!=""){
        alert("欢迎 " + user + " 再次访问");
    }
    else {
        user = prompt("请输入你的名字:","");
          if (user!="" && user!=null){
            setCookie("username",user,30);
        }
    }
}

//保存数据  
function save(){  
    var site = new Object;
    site.keyname = document.getElementById("keyname").value;
    site.sitename = document.getElementById("sitename").value;  
    site.siteurl = document.getElementById("siteurl").value;
    var str = JSON.stringify(site); // 将对象转换为字符串
    localStorage.setItem(site.keyname,str);  
    alert("保存成功");
}  
//查找数据  
function find(){  
    var search_site = document.getElementById("search_site").value;  
    var str = localStorage.getItem(search_site);  
    var find_result = document.getElementById("find_result");
    var site = JSON.parse(str);  
    find_result.innerHTML = search_site + "的网站名是：" + site.sitename + "，网址是：" + site.siteurl;  
}