问题描述

使用JQuery对html中的ul进行li的增删改以及遍历查看

代码

html部分

<div>
        <ul>
        </ul>
    </div>
    <button id="addItem">添加元素</button>
    <button id="deleteItem">删除元素</button>
    <button id="traversal">显示列表</button>
    <input type="text" placeholder="输入修改第几项" id="index">
    <input type="text" placeholder="修改的值" id="value">
    <button id="modifyItem">改变列表项</button>
    <br>遍历结果：
    <p id="res"></p>

script部分

list增加元素：

$("#addItem").click(function() {
                let newItem = "";
                newItem = "<li>" + i + "</li>";
                i += 1;
                $("ul").append(newItem);
            });

list删除元素：

$("#deleteItem").click(function() {
                let tmp = $("ul").html().toString();
                let location = tmp.lastIndexOf('<li>');
                $('ul').html(tmp.slice(0, location));
                i -= 1;
            });

list修改特定项的元素：

$("#modifyItem").click(function() {
                let index = $("#index").val();
                let value = $("#value").val();
                $("li").eq(index - 1).text(value);
            });

list遍历：

$("#traversal").click(function() {
                let res = [];
                for (j = 0; j < $("li").length; j++) {
                    res.push($("li").eq(j).text())
                }
                $("#res").text(res);
            });

全部代码

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"></script>
    <script>
        $(document).ready(function() {
            let n = 6,
                i = 1;
            let text = "";
            for (i; i < n; i++) {
                text += "<li>" + i + "</li>";
            }
            $("ul").append(text);
            $("#addItem").click(function() {
                let newItem = "";
                newItem = "<li>" + i + "</li>";
                i += 1;
                $("ul").append(newItem);
            });
            $("#deleteItem").click(function() {
                let tmp = $("ul").html().toString();
                let location = tmp.lastIndexOf('<li>');
                $('ul').html(tmp.slice(0, location));
                i -= 1;
            });
            $("#traversal").click(function() {
                let res = [];
                for (j = 0; j < $("li").length; j++) {
                    res.push($("li").eq(j).text())
                }
                $("#res").text(res);
            });
            $("#modifyItem").click(function() {
                let index = $("#index").val();
                let value = $("#value").val();
                $("li").eq(index - 1).text(value);
            })
        })
    </script>
</head>

<body>
    <p>July 16th</p>
    <div>
        <ul>
        </ul>
    </div>
    <button id="addItem">添加元素</button>
    <button id="deleteItem">删除元素</button>
    <button id="traversal">显示列表</button>
    <input type="text" placeholder="输入修改第几项" id="index">
    <input type="text" placeholder="修改的值" id="value">
    <button id="modifyItem">改变列表项</button>
    <br>遍历结果：
    <p id="res"></p>
</body>
</html>