访问器属性计算商品价格

            let shop = {
                data: [{
                    id: 1,
                    name: "西红柿",
                    price: 2,
                    quantity: 0
                }],
                get price() {
                    return this.data[0].price;
                },
                set price(num) {
                    this.data[0].quantity = num;
                    let sum = this.data[0].price * num;
                    this.data[0].price = sum;
                }
            }
            shop.price = 30;
            console.log(`购买了${shop.data[0].quantity}个西红柿，一共${shop.price}元！`);
            // 打印输出：购买了30个西红柿，一共60元！
        </script>

dom元素的获取、遍历、增加

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
    </head>
    <body>
        <ul id="list">
            <li>第1行</li>
            <li>第2行</li>
            <li>第3行</li>
            <li>第4行</li>
            <li>第5行</li>
        </ul>
        <script type="text/javascript">
            let lis = document.querySelector("#list")
            const list = document.querySelectorAll("#list li"); // 获取
            console.log(list);
            list.forEach((item, i) => { // 遍历
                item.style.background = "red"
            })
            document.body.style.background = "cadetblue"
            // 创建元素
            let newLi = document.createElement("li");
            newLi.textContent = "第6行";
            lis.insertAdjacentElement("beforeEnd", newLi);
        </script>
        <!-- 获取表单元素 -->
        <form action="" name="login" id="mylogin">
            <input type="text" name="text" value="hahahah">
            <button>提交</button>
        </form>
        <script type="text/javascript">
            console.log(document.forms.login.text.value); // 获取表单元素
        </script>
    </body>
</html>

属性访问器和dom元素的获取、遍历、增加

访问器属性 计算商品价格

dom元素的获取、遍历、增加

访问器属性计算商品价格