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

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

//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');