localStorage存值取值以及存取JSON,以及基于html5 localStorage的购物车[转]

localStorage.setItem("key","value");//存储变量名为key，值为value的变量  
   
localStorage.key = "value"//存储变量名为key，值为value的变量  
   
localStorage.getItem("key");//获取存储的变量key的值www.it165.net  
   
localStorage.key;//获取存储的变量key的值  
   
localStorage.removeItem("key")//删除变量名为key的存储变量  
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---
//以上即为localStorage调用的方法。下面介绍存储JSON对象的方法。  
var students =   
{  
    liyang:{name:"liyang",age:17},  
  
    lilei:{name:"lilei",age:18}  
  
}//要存储的JSON对象  
  
  
students = JSON.stringify(students);//将JSON对象转化成字符串  
  
localStorage.setItem("students",students);//用localStorage保存转化好的的字符串  

--
//上面即可保存JSON对象，接下来我们在要使用的时候再将存储好的students变量取回  
   
var students = localStorage.getItem("students");//取回students变量  
   
students = JSON.parse(students);//把字符串转换成JSON对象  
   
//以上即可得到存储的students的JSON对象了  

---
utils = {  
    setParam : function (name,value){  
        localStorage.setItem(name,value)  
    },  
    getParam : function(name){  
        return localStorage.getItem(name)  
    }  
}  
  
product={  
    id:0,  
    name:"",  
    num:0,  
    price:0.00  
};  
orderdetail={  
    username:"",  
    phone:"",  
    address:"",  
    zipcode:"",  
    totalNumber:0,  
    totalAmount:0.00      
}  
cart = {  
    //向购物车中添加商品  
    addproduct: function (product) {  
        var ShoppingCart = utils.getParam("ShoppingCart");  
        if (ShoppingCart == null || ShoppingCart == "") {  
            //第一次加入商品  
            var jsonstr = { "productlist": [{ "id": product.id, "name": product.name, "num": product.num, "price": product.price}], "totalNumber": product.num, "totalAmount": (product.price * product.num) };  
            utils.setParam("ShoppingCart", "'" + JSON.stringify(jsonstr));  
        } else {  
            var jsonstr = JSON.parse(ShoppingCart.substr(1, ShoppingCart.length));  
            var productlist = jsonstr.productlist;  
            var result = false;  
            //查找购物车中是否有该商品  
            for (var i in productlist) {  
                if (productlist[i].id == product.id) {  
                    productlist[i].num = parseInt(productlist[i].num) + parseInt(product.num);  
                    result = true;  
                }  
            }  
            if (!result) {  
                //没有该商品就直接加进去  
                productlist.push({ "id": product.id, "name": product.name, "num": product.num, "price": product.price });  
            }  
            //重新计算总价  
            jsonstr.totalNumber = parseInt(jsonstr.totalNumber) + parseInt(product.num);  
            jsonstr.totalAmount = parseFloat(jsonstr.totalAmount) + (parseInt(product.num) * parseFloat(product.price));  
            orderdetail.totalNumber = jsonstr.totalNumber;  
            orderdetail.totalAmount = jsonstr.totalAmount;  
            //保存购物车  
            utils.setParam("ShoppingCart", "'" + JSON.stringify(jsonstr));  
        }  
    },  
    //修改给买商品数量  
    updateproductnum: function (id, num) {  
        var ShoppingCart = utils.getParam("ShoppingCart");  
        var jsonstr = JSON.parse(ShoppingCart.substr(1, ShoppingCart.length));  
        var productlist = jsonstr.productlist;  
  
        for (var i in productlist) {  
            if (productlist[i].id == id) {  
                jsonstr.totalNumber = parseInt(jsonstr.totalNumber) + (parseInt(num) - parseInt(productlist[i].num));  
                jsonstr.totalAmount = parseFloat(jsonstr.totalAmount) + ((parseInt(num) * parseFloat(productlist[i].price)) - parseInt(productlist[i].num) * parseFloat(productlist[i].price));  
                productlist[i].num = parseInt(num);  
                orderdetail.totalNumber = jsonstr.totalNumber;  
                orderdetail.totalAmount = jsonstr.totalAmount;  
                utils.setParam("ShoppingCart", "'" + JSON.stringify(jsonstr));  
                return;  
            }  
        }  
    },  
    //获取购物车中的所有商品  
    getproductlist: function () {  
        var ShoppingCart = utils.getParam("ShoppingCart");  
        var jsonstr = JSON.parse(ShoppingCart.substr(1, ShoppingCart.length));  
        var productlist = jsonstr.productlist;  
        orderdetail.totalNumber = jsonstr.totalNumber;  
        orderdetail.totalAmount = jsonstr.totalAmount;  
        return productlist;  
    },  
    //判断购物车中是否存在商品  
    existproduct: function (id) {  
        var result = false;  
        var ShoppingCart = utils.getParam("ShoppingCart");  
        if (ShoppingCart != null) {  
            var jsonstr = JSON.parse(ShoppingCart.substr(1, ShoppingCart.length));  
            var productlist = jsonstr.productlist;  
            for (var i in productlist) {  
                if (productlist[i].id == id) {  
                    result = true;  
                }  
            }  
        }  
        return result;  
    },  
    //删除购物车中商品  
    deleteproduct: function (id) {  
        var ShoppingCart = utils.getParam("ShoppingCart");  
        var jsonstr = JSON.parse(ShoppingCart.substr(1, ShoppingCart.length));  
        var productlist = jsonstr.productlist;  
        var list = [];  
        for (var i in productlist) {  
            if (productlist[i].id == id) {  
                jsonstr.totalNumber = parseInt(jsonstr.totalNumber) - parseInt(productlist[i].num);  
                jsonstr.totalAmount = parseFloat(jsonstr.totalAmount) - parseInt(productlist[i].num) * parseFloat(productlist[i].price);  
            } else {  
                list.push(productlist[i]);  
            }  
        }  
        jsonstr.productlist = list;  
        orderdetail.totalNumber = jsonstr.totalNumber;  
        orderdetail.totalAmount = jsonstr.totalAmount;  
        utils.setParam("ShoppingCart", "'" + JSON.stringify(jsonstr));  
    }  
};  

-----------
//上面的基于html5 localStorage的购物车JS脚本使用方法  
var product =  
{  
    'id': id,        //属性名用引号括起来，属性间由逗号隔开  
    'name': 'hhh',  
    'num':jq('#text-4').val(),  
    'price':199.9  
};  
//商品加入到购物车  
cart.addproduct(product);  
var productlist=cart.getproductlist();//取出购物车商品  
alert('', '商品:'+productlist[0].id+' '+productlist[0].name+' '+productlist[0].num+' '+productlist[0].price, '确定');