Java基础之JavaScript——练习题

1、电灯开关

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

    <img id="light" src="img/off.gif">

</body>

<script>
    /*
        1、获取图片对象
          2、绑定点击事件
           3、切换图片
                使用flag标注状态
    * */
        var element = document.getElementById("light");
        var flag = false;//关闭状态
    //2、绑定点击事件
        element.onclick = function (ev) {
            if(flag){//如果灯开着
                element.src = "img/off.gif";
                flag = false;
            }else{
                element.src = "img/on.gif";
                flag = true;
            }

        }


</script>
</html>

2、5s以后弹出图片

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

    <div  style="text-align: center "><span  id="time" style="font-size: 100px">5</span></div>
    <img id="img" src="img/gui.jpg" style="display: none">

</body>

<script>
        var time = document.getElementById("time");
        var img = document.getElementById("img");
        var num = time.innerHTML;
        setInterval(function () {
            if(num>1){
                num--;
                time.innerHTML = num;
            }else{
                img.style.display = "block";
            }
        },1000);
</script>
</html>

3、轮播图

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <img id="img" src="img/banner_1.jpg">

</body>

<script>

        var img = document.getElementById("img");
        var num = 1;
        setInterval(function () {
           num++;
           //判断num和3的大小
            if(num>3){
                num = 1;
            }
            img.src = "img/banner_"+num+".jpg";
        },2000);
</script>
</html>

4、省级联动

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
   <select id="pro" onchange="choice()">
       <option value="sc">四川</option>
       <option value="cq">重庆</option>
       <option value="gd">广东</option>
   </select>

   <select id="city">
       <option>成都</option>
       <option>德阳</option>
       <option>绵阳</option>
   </select>

</body>

<script>

    var pro = document.getElementById("pro");
    var city = document.getElementById("city");

    function choice() {
        var _pro = pro.value
        switch (_pro) {
            case "sc":
                city.innerHTML = "<option>成都</option>\n" +
                    "       <option>德阳</option>\n" +
                    "       <option>绵阳</option>"
                break;
            case "cq":
                city.innerHTML = "<option>重庆</option>";
                break;
            case "gd":
                city.innerHTML = "<option>广州</option>\n" +
                    "       <option>深圳</option>\n" +
                    "       <option>东莞</option>"
                break;
        }
    }
</script>
</html>

5、表格的增删

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>


        table{
            border: 1px solid;
            margin : auto;
            width: 500px;
        }
        td{
            border: 1px solid;
        }
        div{
            text-align: center;
        }
    </style>
</head>
<body>

        <div>
            <input type="text" id="id" placeholder="请输入编号">
            <input type="text" id="name" placeholder="请输入名字">
            <input type="text" id="gender" placeholder="请输入性别">
            <input type="button" id="add" value="添加" onclick="add()">
        </div>

    <table>
        <tr>
            <td>id</td>
            <td>name</td>
            <td>gender</td>
            <td>delete</td>
        </tr>
        <tr>
            <td>1</td>
            <td>coco</td>
            <td>女</td>
            <td><a href="javascript:void(0)" onclick="del(this)">删除</a></td>
        </tr>
        <tr>
            <td>2</td>
            <td>bobo</td>
            <td>男</td>
            <td><a href="javascript:void(0)" onclick="del(this)">删除</a></td>
        </tr>
        <tr>
            <td>3</td>
            <td>yoyo</td>
            <td>女</td>
            <td><a href="javascript:void(0)" onclick="del(this)">删除</a></td>
        </tr>
    </table>

</body>

<script>
        function del(obj) {
            var table = obj.parentNode.parentNode.parentNode;
            var tr = obj.parentNode.parentNode;
            table.removeChild(tr);
        }

        function add() {
            var id = document.getElementById("id").value;
            var name = document.getElementById("name").value;
            var gender = document.getElementById("gender").value;

            var table = document.getElementsByTagName("table")[0];
            //追加一行
            table.innerHTML += " <tr>\n" +
                "            <td>"+id+"</td>\n" +
                "            <td>"+name+"</td>\n" +
                "            <td>"+gender+"</td>\n" +
                "            <td><a href=\"javascript:void(0)\" onclick=\"del(this)\">删除</a></td>\n" +
                "        </tr>"

        }
</script>
</html>

6、表格的全选与全不选

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>


        table{
            border: 1px solid;
            margin : auto;
            width: 500px;
        }
        td{
            border: 1px solid;
        }

    </style>
</head>
<body>


    <table>
        <tr>
            <td></td>
            <td>id</td>
            <td>name</td>
            <td>gender</td>
            <td>delete</td>
        </tr>
        <tr>
            <td><input type="checkbox" name="choice" ></td>
            <td>1</td>
            <td>coco</td>
            <td>女</td>
            <td><a href="javascript:void(0)" onclick="del(this)">删除</a></td>
        </tr>
        <tr>
            <td><input type="checkbox" name="choice"></td>
            <td>2</td>
            <td>bobo</td>
            <td>男</td>
            <td><a href="javascript:void(0)" onclick="del(this)">删除</a></td>
        </tr>
        <tr>
            <td><input type="checkbox" name="choice"></td>
            <td>3</td>
            <td>yoyo</td>
            <td>女</td>
            <td><a href="javascript:void(0)" onclick="del(this)">删除</a></td>
        </tr>
    </table>
    <center>
    <button id="qx">全选</button>
    <button id="qbx">全不选</button>
    <button id="fx">反选</button>
    </center>
</body>

<script>
    document.getElementById("qx").onclick = function () {
        var checkboxs = document.getElementsByName("choice");
        for (var i = 0;i<checkboxs.length;i++){
            checkboxs[i].checked = true;
        }

    }

    document.getElementById("qbx").onclick = function () {
        var checkboxs = document.getElementsByName("choice");
        for (var i = 0;i<checkboxs.length;i++){
            checkboxs[i].checked = false;
        }

    }

    document.getElementById("fx").onclick = function () {
        var checkboxs = document.getElementsByName("choice");
        for (var i = 0;i<checkboxs.length;i++){
            checkboxs[i].checked = !checkboxs[i].checked;
        }

    }

    var trs = document.getElementsByTagName("tr");
    for (var i = 0;i<trs.length;i++){
            trs[i].onmouseover = function (ev) {
                this.style.background = "red"
            }

            trs[i].onmouseout = function (ev) {
                this.style.background = "white"

            }
    }
</script>
</html>

7、表单的验证

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>

    <form id="form">

        用户名:<input type="text" id="username" name="name" onblur="checkName()">
        <span id="sp_name"></span>
        <br>
        <input type="submit">

    </form>

</body>

<script>
    window.onload = function (ev) {

        document.getElementById("form").onsubmit = function (ev1) {

            return checkName();
        }

    }

    function checkName() {
        var useranme = document.getElementById("username").value;
        var sp_name= document.getElementById("sp_name");
        var regExp = new RegExp("^.{3,20}$");
        if(regExp.test(useranme)){
            sp_name.innerHTML = "可以注册";
            sp_name.style.color = "green";
            return true;
        }else{
            sp_name.innerHTML = "用户名格式有误";
            sp_name.style.color = "red";
            return false;
        }
    }
</script>
</html>

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转载自blog.csdn.net/qq_36095679/article/details/86591508