• JS案例:购物车操作(简单实现)


    Html:

    <!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <meta http-equiv="X-UA-Compatible" content="ie=edge" />
        <title>shop</title>
        <link rel="stylesheet" href="css/shop.css">
      </head>
    
      <body>
        <script src="js/shop.js"></script>
        <script>
          // 新建数据
          var obj = [
            {
              select: false,
              img:"img/1.jpg",//图片路径
              name: "OPPO R11 全网通4G 双卡双待手机玫瑰金色",
              price: 2799,
              num: 1,
              sum: 0,
              del: false
            },
            {
              select: false,
              img:"img/2.jpg",//图片路径
              name: "Apple iPhone8 64G 金色 移动联通电信4G手机",
              price: 5888,
              num: 1,
              sum: 0,
              del: false
            }
          ];
          // 实例化对象,传入数据
          var table = new Table(obj);
        </script>
      </body>
    </html>
    

    Css:

    *{
        margin: 0;
        padding: 0;
    }
    table{
         1200px;
        /* background: lightcoral; */
        margin: 50px auto;
    }
    tr:nth-child(1){
        background: #F3F3F3;
        height: 26px;
    }
    img{
        height: 30%;
        vertical-align: middle;
    }
    img+span{
        font-size: 10px;
    }
    td{
        text-align: center;
        vertical-align: middle;
    }
    tr td:nth-child(2){
        text-align: left;
    }
    tr td:nth-child(4) div button{
        height: 20px;
         20px;
        border: none;
        text-align: center;
        vertical-align: middle;
    }
    tr td:nth-child(4) div input{
        height: 20px;
         27px;
        vertical-align: middle;
    }
    tr td:nth-child(3),tr td:nth-child(5){
         100px;
    }
    table>div{
         300px;
        text-align: right;
    }

    JS:

    function Table(obj) {
      this.obj = obj; //引入数组对象
      this.init(obj); //入口函数
    }
    Table.prototype = {
      table: null, //初始化表格
      allSum: 0, //商品总和
      allNum: 0, //商品数量总和
      allselect: false, //全选
      init: function (obj) {
        this.createTab(obj); //创建表格
      },
      createTab: function (obj) {
        if (this.table) { //初始化表格,若表格存在,则删除表格再新建
          this.table.remove();
          this.table = null;
        }
        this.table = document.createElement("table"); //创建表格
        var thr = document.createElement("tr"); //创建表格标题
        var selectAll = document.createElement("th");
        var selectAllInput = document.createElement("input"); //全选
        selectAllInput.self = this;
        selectAllInput.addEventListener("change", this.selectHandler); //添加事件,当全选建改变时触发
        selectAllInput.type = "checkbox";
        selectAllInput.checked = this.allselect; //给其选中添加值,让数据驱动更改选中状态
        selectAll.textContent = "全选";
        selectAll.appendChild(selectAllInput);
        thr.appendChild(selectAll); //createName方法添加表头内容
        this.createName("商品", thr);
        this.createName("单价", thr);
        this.createName("数量", thr);
        this.createName("小计", thr);
        this.createName("操作", thr);
        this.table.appendChild(thr);
        for (var i = 0; i < obj.length; i++) { //根据数组对象创建表格
          var tr = document.createElement("tr");
          for (var str in obj[i]) { //跳过name那项(因为里面有两个属性,后面会讲到)
            if (str === "name") continue;
            var td = document.createElement("td");
            if (str === "select") { //当属性名为select时创建多选按钮,添加更改时触发的事件
              var select = document.createElement("input");
              select.type = "checkbox";
              select.self = this;
              select.index = i; //传递当前点击索引
              select.addEventListener("change", this.selectHandler);
              select.checked = obj[i].select; //给其选中添加值,让数据驱动更改选中状态
              td.appendChild(select);
            } else if (str === "img") { //当属性名为img时创建图片以及商品名
              var img = new Image();
              img.src = obj[i][str];
              var name = document.createElement("span");
              name.textContent = obj[i].name;
              td.appendChild(img);
              td.appendChild(name);
            } else if (str === "price") { //当属性名为price时创建价格,同样数据驱动
              td.price = obj[i][str];
              td.textContent = td.price;
            } else if (str === "num") { //数据驱动商品的个数
              var num = document.createElement("div");
              num.index = i;
              num.data = obj; //将数据赋给num(后面会用到)
              num.self = this;
              //创建-和+按钮,以及文本框,改变商品个数
              var left = document.createElement("button");
              var text = document.createElement("input");
              var right = document.createElement("button");
              left.textContent = "-";
              right.textContent = "+";
              text.value = obj[i].num;
              //添加事件,当点击+或-时触发事件,当文本框中失焦触发另一个事件
              left.addEventListener("click", this.changeNum);
              text.addEventListener("blur", this.changeNum);
              right.addEventListener("click", this.changeNum);
              num.appendChild(left);
              num.appendChild(text);
              num.appendChild(right);
              td.appendChild(num);
            } else if (str === "sum") { //新建单商品的总价(个数乘以单价)
              var sum = document.createElement("div");
              sum.data = obj[i]; //将该商品的数据传递
              sum.textContent = obj[i].num * obj[i].price;
              td.appendChild(sum);
            } else if (str === "del") { //新建删除按钮
              var del = document.createElement("button");
              del.textContent = "Del";
              del.data = obj; //将该商品的数据传递
              del.index = i; //该项的索引通过事件传递
              del.self = this;
              del.addEventListener("click", this.delHandler); //删除事件
              td.appendChild(del);
            }
            tr.appendChild(td);
          }
          this.table.appendChild(tr);
        }
        this.addAll(obj, this.table); //根据更新的表格数据新建商品总价及总个数
        document.body.appendChild(this.table);
        return this.table;
      },
      addAll: function (obj, parent) { //商品总价及总个数
        var addAllItem = document.createElement("div");
        var addAllPrice = document.createElement("div");
        var sum = 0; //初始化总价及数量
        var price = 0;
        for (var i = 0; i < obj.length; i++) {
          sum += obj[i].num;
          price += obj[i].price * obj[i].num; //求总价和总和
        }
        addAllItem.textContent = "总数:" + sum;
        addAllPrice.textContent = "总价:" + price;
        parent.appendChild(addAllItem);
        parent.appendChild(addAllPrice);
      },
      createName: function (text, parent) { //createName方法添加表头内容
        var item = document.createElement("th");
        item.textContent = text;
        parent.appendChild(item);
        return item;
      },
      changeNum: function (e) {
        if (this.textContent === "+") { //当点击+按钮使数组对象中的商品数加一,当商品数量大于99就不再增加
          this.parentNode.data[this.parentNode.index].num++;
          if (this.parentNode.data[this.parentNode.index].num > 99) {
            this.parentNode.data[this.parentNode.index].num = 99;
          }
        } else if (this.textContent === "-") { //当点击-按钮使数组对象中的商品数减一,当商品数量小于0就不再减少
          this.parentNode.data[this.parentNode.index].num--;
          if (this.parentNode.data[this.parentNode.index].num < 1) {
            this.parentNode.data[this.parentNode.index].num = 1;
          }
        } else { //当在文本框输入个数时对数组对象中的商品数进行操作
          if (isNaN(this.value)) { //当输入的不为数值时,使其变成1
            this.parentNode.data[this.parentNode.index].num = 1;
          } else if (Number(this.value) > 99) { //当输入的大于99时,使其变成99
            this.parentNode.data[this.parentNode.index].num = 99;
          } else if (Number(this.value) < 1) { //当输入的小于1时,使其变成1
            this.parentNode.data[this.parentNode.index].num = 1;
          } else { //否则直接让对象中的数值等于输入的值
            this.parentNode.data[this.parentNode.index].num = Number(this.value);
          }
        }
        this.parentNode.self.init(this.parentNode.data); //根据更改后的数据驱动创建表格
      },
      delHandler: function (e) {
        this.data.splice(this.index, 1); //删除当前选择的那项,根据更改后的数据驱动创建表格
        this.self.init(this.data);
      },
      selectHandler: function (e) { //全选时使所有的单选框都根据数据更改
        if (this.parentNode.textContent === "全选") {
          this.self.allselect = !this.self.allselect;
          for (var i = 0; i < this.self.obj.length; i++) {
            this.self.obj[i].select = this.self.allselect;
          }
        } else {
          var sum = 1; //当所有的单选框选中的值为true时,将全选选中(true是1,false是0)
          this.self.obj[this.index].select = !this.self.obj[this.index].select;
          for (var i = 0; i < this.self.obj.length; i++) {
            sum *= this.self.obj[i].select;
          }
          if (sum) {
            this.self.allselect = true;
          } else {
            this.self.allselect = false;
          }
        }
        this.self.init(this.self.obj); //根据更改后的数据驱动创建表格
        console.log(this.checked);
      }
    };
    Table.prototype.constructor = Table;
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  • 原文地址:https://www.cnblogs.com/HelloWorld-Yu/p/10193687.html
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