我用JS+Cookie編寫的購物車，（添加、修改過程在用戶端執行，一次提交伺服器，IE適用），請大家指正（二）

cookie|js|伺服器|購物車|過程|用戶端|執行 二、js函數：orderform_functions.js

//Vampirebat,2002-1-16;http://www.vampirebat.org

//<--Start--從cookie中讀出訂單資料的函數
function ReadOrderForm(name)
{
    var cookieString=document.cookie;
    if (cookieString=="")
    {
        return false;
    }
    else
    {
        var firstChar,lastChar;
        firstChar=cookieString.indexOf(name);
        if(firstChar!=-1)
        {
            firstChar+=name.length+1;
            lastChar = cookieString.indexOf(';', firstChar);
            if(lastChar == -1) lastChar=cookieString.length;
            return cookieString.substring(firstChar,lastChar);
        }
        else
        {
            return false;
        }
    }    
}
//-->End

//<--Start--添加商品至購物車的函數
function SetOrderForm(item_no,item_name,item_amount,item_price)
{
    var cookieString=document.cookie;
    if (cookieString.length>=4000)
    {
        alert("您的訂單已滿\n請結束此次訂單操作後添加新訂單！");
    }
    else if(isNaN(item_amount)||item_amount<1||item_amount.indexOf('.')!=-1)
    {
        alert("數量輸入錯誤！");
    }
    else
    {
        var mer_list=ReadOrderForm('24_OrderForm');
        var Then = new Date();
        Then.setTime(Then.getTime()+30*60*1000);
        var item_detail="|"+item_no+"&"+item_name+"&"+item_amount+"&"+item_price;
        if(mer_list==false)
        {
            document.cookie="24_OrderForm="+escape(item_detail)+";expires=" + Then.toGMTString();
            alert("“"+item_name+"”\n"+"已經加入您的訂單！");
        }
        else
        {
            if (mer_list.indexOf(item_no)!=-1)
            {
                alert('此商品您已添加\n請進入訂單修改數量！')
            }
            else
            {
                document.cookie="24_OrderForm="+mer_list+escape(item_detail)+";expires=" + Then.toGMTString();
                alert("“"+item_name+"”\n"+"已經加入您的訂單！");
            }
        }
    }
}
//-->End

//<--Start--訂單修改更新cookie的函數
function updateCookie()
{
    var limit=document.OrderForm.elements.length-3;
    if (document.OrderForm.update.value=="修改訂單")