How to use JavaScript to complete the linkage effect of provinces and cities-JS Tutorial-php.cn

How to use JavaScript to complete the linkage effect of provinces and cities

藏色散人

Release： 2020-05-08 16:51:40

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Province and city linkage effect

[DOM operations in HTML]

Some commonly used HTML DOM methods:

getElementById(id) - Get the node (element) with the specified id

appendChild(node) - Insert a new child node (element)

removeChild(node) - Remove the child node (element)

Some commonly used HTML DOM attributes:

innerHTML - the text value of the node (element)

parentNode - the parent node of the node (element)

childNodes - the node (element) )'s child node

attributes - the attribute node of the node (element)

Find the node:

getElementById() Returns the element with the specified ID.

getElementsByTagName() Returns a node list (collection/node array) containing all elements with the specified tag name.

getElementsByClassName() Returns a node list containing all elements with the specified class name.

Add node:

createAttribute() creates an attribute node.

createElement() Creates an element node.

createTextNode() Creates a text node.

insertBefore() Inserts a new child node before the specified child node.

appendChild() Adds a new child node to the specified node.

Delete node:

removeChild() deletes the child node.

replaceChild() Replaces child nodes.

Modify node:

setAttribute() Modify attribute

setAttributeNode() Modify attribute node

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script>
/*动态添加 :   <p>文本</p> */
function dianwo(){
var div = document.getElementById("div1");
//创建元素节点
var p = document.createElement("p");  // <p></p>
//创建文本节点
var textNode = document.createTextNode("文本内容");//  文本内容
//将p 和文本内容关联起来
p.appendChild(textNode);  //  <p>文本</p> 
//将P添加到目标div中
div.appendChild(p);
}
</script>
</head>
<body>
<input type="button" value="点我,添加P" onclick="dianwo()" />
<!--一会动态的往这个Div中添加节点-->
<div id="div1">
</div>
</body>
</html>

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Code implementation

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script>
/*
准备工作 : 准备数据
*/
var provinces = [
["深圳市","东莞市","惠州市","广州市"],
["长沙市","岳阳市","株洲市","湘潭市"],
["厦门市","福州市","漳州市","泉州市"]
];
/*
1. 确定事件:  onchange
2. 函数: selectProvince()
3. 函数里面要搞事情了
得到当前操作元素
得到当前选中的是那一个省份
从数组中取出对应的城市信息
动态创建城市元素节点
添加到城市select中
*/
function selectProvince(){
var province = document.getElementById("province");
//得到当前选中的是哪个省份
//alert(province.value);
var value = province.value;
//从数组中取出对应的城市信息
var cities = provinces[value];
var citySelect = document.getElementById("city");
//清空select中的option
citySelect.options.length = 0;
for (var i=0; i < cities.length; i++) {
//alert(cities[i]);
var cityText = cities[i]; 
//动态创建城市元素节点   <option>东莞市</option>
//创建option节点
var option1 = document.createElement("option"); // <option></option>
//创建城市文本节点
var textNode = document.createTextNode(cityText) ;// 东莞市
//将option节点和文本内容关联起来
option1.appendChild(textNode);  //<option>东莞市</option>
//添加到城市select中
citySelect.appendChild(option1);
}
}
</script>
</head>
<body>
<!--选择省份-->
<select onchange="selectProvince()" id="province">
<option value="-1">--请选择--</option>
<option value="0">广东省</option>
<option value="1">湖南省</option>
<option value="2">福建省</option>
</select>
<!--选择城市-->
<select id="city"></select>
</body>
</html>

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How to use JavaScript to complete the linkage effect of provinces and cities

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