"Uncaught TypeError: Failed to execute 'setAttribute' on 'Element': 2 arguments required, but only 1 present."意思是setAttribute需要傳入兩個參數，但僅傳入一個。該錯誤是由於setAttribute里傳入的參數不全或者錯誤導致。
<body>
<div class="contain">
<div class="shop">
</div>
<div class="button copy">
<input type="checkbox" />
<label>全選</label>
<label>總價：<span id="allPrice">0</span>元</label>
<label>結算：<span>0</span>元</label>
</div>
</div>
</body>
shopContain = document.getElementsByClassName("shop")[0];//shop節點
subBtn=document.getElementsByClassName('sub');//sub按鈕節點（通過拼接字符串添加）
var arrObj = [
{
shopName:"鑽石",
shopImg:"img/hot1.jpg",
shopPrice:1000,
shopCount:1,
},
{
shopName:"黃金",
shopImg:"img/hot1.jpg",
shopPrice:2000,
shopCount:1,
}
]
//拼接字符
for (var i = 0; i < arrObj.length; i++) {
var itemObj=arrObj[i];
var chcked ='<input type="checkbox" />';
var shopNameStr = "<label>商品名稱："+itemObj["shopName"]+"</label>";
var shopImgStr = "<label><img src="+itemObj["shopImg"]+"></label>"
var shopPriceStr = "<label>價格：<span>"+itemObj["shopPrice"]+"元</span></label>";
var shopCountStr = '<label>數量：<button class="sub" disabled="disabled" >-</button><span>'+itemObj["shopCount"]+'個</span><button class="add">+</button></label>';
var divStr = "<div>"+chcked+shopNameStr+shopImgStr+shopPriceStr+shopCountStr+"</div>";
shopContain.innerHTML+= divStr;
}
for (var i = 0; i < subBtn.length; i++) {
subBtn[i].onclick=sub;
console.log(subBtn[i])
//對於自定義的屬性，應該通過setAttribute方法來添加到元素節點中，否則就無法獲取該屬性，要想獲取自定義屬
//性的值，應該在setAttribute(參數1，參數2)中傳入參數2的值(注：參數1：自定義的屬性，參數2：給自定義屬
//性設置的值),這樣才能subBtn.index，獲取自定義屬性index的值，可以寫成以下寫法
subBtn[i].setAttribute("index",i)
subBtn.index=i
addBtn[i].onclick=add;
}