js 枚举怎么用( 二 ) _电脑

var opt2 = document.createElement("option");
opt2.value = https://vvvtt.com/article/key;
opt2.innerText = ds[key];
selector2.appChild(opt2);
}

}
</script>
</body>
</html>

3第三步：测试省市级联。
打开网页--查看默认市级下拉框--》在别离选择河南省和河海说神聊省查看市级下拉框的转变。结论是市级下拉框会随省的改变而改变。具体操作成果如下图所示：

4第四步：当做面标的目的对象的实体类利用。
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>

</body>

<script>
//界说学生小明
var student ={name:"小明",sex:"男",age:"10"};
console.log("name:"+student.name+" sex:"+student.sex)

//界说多个学生，也就是学生数组
var students = [
{name:"小亮",sex:"男",age:"11"},
{name:"小美",sex:"女",age:"12"}
];

console.log("-----------------------------获取第一个小亮信息--------------------------------")
var xiaoliang = students[0];
console.log("name:"+xiaoliang.name+" sex:"+xiaoliang.sex)

//声明一个空的json数据
var testJson = {};

testJson.student = student;
testJson.students = students;
console.log(testJson)

//新增
testJson.student.test = {test:"测试"};
testJson.students.push(student);
console.log(testJson)

//点窜
testJson.student.test={test:"测试2"}
console.log(testJson)

//删除
delete testJson.student["test"];
console.log(testJson)

//移除数组中所有json数据
//testJson.students.splice(0,testJson.students.length);
console.log(testJson)

</script>
</html>

js 枚举怎么用( 二 )

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