JavaScript实现的一些小案例

小案例

灯开关案例

<body><img id="light" src="img/off.jpg"><script>var light = document.getElementById("light");var flag = false;if(flag){light.src = "img/on.jpg";flag = false;}else{light.src = "img/off.jpg";flag = true;}	</script>
</body>

轮播图案例

<body><img src="../../../../imgs/banner_1.jpg" width="100%" id="img"><script>var number = 1;/*修改图片*/function fun(){number ++;if(number > 3){number = 1;}var img = document.getElementById("img");img.src = "../../../../imgs/banner_"+ number +".jpg";}setInterval(fun,3000);</script>
</body>

自动跳转案例

p{text-align: center;font-size: 20px;
}
#time{color: red;
}

<p><span id="time">5</span>秒之后跳转到首页
</p>
<script>var time = document.getElementById("time");var number = 5;function fun(){number --;if(number <= 0){//跳转页面location.href="https://www.baidu.com";}//修改标签体里的内容time.innerHTML = number + "";}//设置定时器setInterval(fun,1000);
</script>

动态表格

样式文件

table{border: 1px solid;margin: auto;width: 500px;
}
td,th{text-align: center;border: 1px solid;
}
div{text-align: center;margin: 50px;
}

html 页面

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>动态表格</title><link rel="stylesheet" href="table.css">
</head>
<body><div><input type="text" id="id" placeholder="请输入编号"><input type="text" id="name" placeholder="请输入姓名"><input type="text" id="gender" placeholder="请输入性别"><input type="button" id="btn_ad" value="添加"></div><table><caption>学生信息表</caption><tr><th>编号</th><th>姓名</th><th>性别</th><th>操作</th></tr><tr><td>1</td><td>令狐冲</td><td>男</td><td><a href="javascript:void(0)" onclick="delTr(this);">删除</a></td></tr><tr><td>2</td><td>任我行</td><td>男</td><td><a href="javascript:void(0)" onclick="delTr(this);">删除</a></td></tr><tr><td>3</td><td>岳不群</td><td>？</td><td><a href="javascript:void(0)" onclick="delTr(this);">删除</a></td></tr></table><script rel="script" src="table.js"></script>
</body>
</html>

JS代码

var btn_add = document.getElementById("btn_ad");
btn_add.onclick = function (){var id = document.getElementById("id").value;var name = document.getElementById("name").value;var gender = document.getElementById("gender").value;var table = document.getElementsByTagName("table")[0];table.innerHTML += "<tr>\n" +"            <td>"+id+"</td>\n" +"            <td>"+name+"</td>\n" +"            <td>"+gender+"</td>\n" +"            <td><a href=\"javascript:void(0)\" οnclick=\"delTr(this);\">删除</a></td>\n" +"        </tr>";
}function delTr(obj){var table = obj.parentNode.parentNode.parentNode;var tr = obj.parentNode.parentNode;table.removeChild(tr);
}