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A case study of simple provincial, city and county three-level linkage functions implemented in JavaScript native code
A case study of simple provincial, city and county three-level linkage functions implemented in JavaScript native code
This article mainly introduces the simple province, city and county three-level linkage function implemented in native JavaScript, and analyzes the implementation method of javascript linkage menu in the form of a complete example, involving javascript events Friends in need can refer to the implementation skills related to response and dynamic operation of page elements.
This article describes the simple province, city and county three-level linkage function implemented in native JavaScript. Share it with everyone for your reference. The details are as follows:
Three-level linkage is indispensable when we write forms. For example, we use it when writing the delivery address. I have been looking at native JavaScript recently. Let’s start with the basics and wait for improvement. Later, we will write a jquery version of
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>三级联动菜单</title>
<style>
select {
font-family: "萝莉体 第二版";
}
.hide {
display: none;
}
</style>
</head>
<body>
<p>
<select id="province">
<option>-请选择-</option>
</select>
<select id="city" class="hide">
<option>-请选择-</option>
</select>
<select id="area" class="hide">
<option>-请选择-</option>
</select>
</p>
<script>
var provinceList = ['北京市', '河北省', '浙江省'];
var cityList = [['东城区', '西城区', '海淀区'], ['廊坊市', '唐山市', '石家庄市', '承德市'], ['杭州市', '温州市', '宁波市', '嘉兴市', '绍兴市']];
var areasList = [
[
['东城区1', '东城区2', '东城区3'],
['西城区1', '西城区2', '西城区3'],
['海淀区1', '海淀区2', '海淀区3']
],
[
['廊坊市1', '廊坊市2', '廊坊市3', '廊坊市4'],
['唐山市1', '唐山市2', '唐山市3', '唐山市4'],
['石家庄市1', '石家庄市2', '石家庄市3', '石家庄市4'],
['承德市1', '承德市2', '承德市3', '承德市4']
],
[
['杭州市1', '杭州市2', '杭州市3', '杭州市4', '杭州市5'],
['温州市1', '温州市2', '温州市3', '温州市4', '温州市5'],
['宁波市1', '宁波市2', '宁波市3', '宁波市4', '宁波市5'],
['嘉兴市1', '嘉兴市2', '嘉兴市3', '嘉兴市4', '嘉兴市5'],
['绍兴市1', '绍兴市2', '绍兴市3', '绍兴市4', '绍兴市5']
]
];
//1.获取元素
var province = document.getElementById("province");
var city = document.getElementById("city");
var area = document.getElementById("area");
//2.给省的选择框赋值,
// ----使用自执行函数，避免污染全局变量-----
(function () {
for (var i = 0; i < provinceList.length; i++) {
var myOption = document.createElement("option");
myOption.innerHTML = provinceList[i];
//设置value值
myOption.value = i;
province.appendChild(myOption);
}
})();
//3.设置选择省的行为函数
province.onchange = function (e) {
city.style.display = "inline-block"; //设置第二个出现
while (city.children.length > 1) { //当省设置为“请选择”时，移除子元素
city.removeChild(city.lastElementChild);
}
while (area.children.length > 1) { //当市设置为“请选择”时，移除子元素
area.removeChild(area.lastElementChild);
}
if (cityList[this.value]) {//当设置为请选择时不显示列表
for (var i = 0; i < cityList[this.value].length; i++) { //添加市的列表
var myOption = document.createElement("option");
myOption.innerHTML = cityList[this.value][i];
//设置value值
myOption.value = i;
city.appendChild(myOption);
}
}
};
//4.设置选择市的行为函数
city.onchange = function (e) {
area.style.display = "inline-block"; //设置第二个出现
while (area.children.length > 1) { //当市设置为“请选择”时，移除子元素
area.removeChild(area.lastElementChild);
}
if (areasList[province.value][this.value]) {//当设置为"请选择"时不显示列表
for (var i = 0; i < areasList[province.value][this.value].length; i++) { //添加市的列表
var myOption = document.createElement("option");
myOption.innerHTML = areasList[province.value][this.value][i];
area.appendChild(myOption);
}
}
}
</script>
</body>
</html>. The running effect diagram is as follows:
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