一个购物车JS脚本，很简单，直接上代码，shoppingCart.js：

    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 ShoppingCart = utils.getParam("ShoppingCart");  
            var jsonstr = JSON.parse(ShoppingCart.substr(1,ShoppingCart.length));  
            var productlist = jsonstr.productlist;  
            var result=false;  
            for(var i in productlist){  
                if(productlist[i].id==product.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));  
        }  
    };  

使用也很简单：

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');