作业
<!DOCTYPE html>
<html>
<head>
<title>完成省城市的三级联动(包括湖南省),附代码和效果图。</title>
</head>
<body>
<select id="province">
<option value="-1">请选择</option>
</select>
<select id="city"></select>
<select id="country"></select>
<script type="text/javascript">
var provinceArr = ['上海','江苏','河北','湖南'];
var cityArr = [
['上海市'],
['苏州市','南京市','扬州市'],
['石家庄','秦皇岛','张家口'],
['长沙市','株洲市','湘潭市']
];
var countryArr =[
[
['黄浦区','静安区','长宁区','浦东区']
],
[
['虎丘区','吴中区','相城区','姑苏区','吴江区'],
['玄武区','秦淮区','建邺区','鼓楼区','浦口区'],
['邗江区','广陵区','江都区']
],
[
['长安区','桥西区','新华区','井陉矿区'],
['海港区','山海关区','北戴河区','抚宁区'],
['桥东区','桥西区','宣化区','下花园区']
],
[
['芙蓉区','岳麓区','天心区','开福区'],
['荷塘区','芦淞区','石峰区','天元区'],
['雨湖区','岳塘区']
]
];
function creatOption(obj,data){
for(var i in data){
var op = new Option(data[i],i);
obj.options.add(op);
}
}
var province = document.getElementById('province');
creatOption(province,provinceArr);
<html>
<head>
<title>完成省城市的三级联动(包括湖南省),附代码和效果图。</title>
</head>
<body>
<select id="province">
<option value="-1">请选择</option>
</select>
<select id="city"></select>
<select id="country"></select>
<script type="text/javascript">
var provinceArr = ['上海','江苏','河北','湖南'];
var cityArr = [
['上海市'],
['苏州市','南京市','扬州市'],
['石家庄','秦皇岛','张家口'],
['长沙市','株洲市','湘潭市']
];
var countryArr =[
[
['黄浦区','静安区','长宁区','浦东区']
],
[
['虎丘区','吴中区','相城区','姑苏区','吴江区'],
['玄武区','秦淮区','建邺区','鼓楼区','浦口区'],
['邗江区','广陵区','江都区']
],
[
['长安区','桥西区','新华区','井陉矿区'],
['海港区','山海关区','北戴河区','抚宁区'],
['桥东区','桥西区','宣化区','下花园区']
],
[
['芙蓉区','岳麓区','天心区','开福区'],
['荷塘区','芦淞区','石峰区','天元区'],
['雨湖区','岳塘区']
]
];
function creatOption(obj,data){
for(var i in data){
var op = new Option(data[i],i);
obj.options.add(op);
}
}
var province = document.getElementById('province');
creatOption(province,provinceArr);
var city = document.getElementById("city");
province.onchange = function(){
city.options.length = 0;
creatOption(city,cityArr[province.value]);
if(province.value >= 0){
city.onchange();
}else{
country.options.length = 0;
}
};
province.onchange = function(){
city.options.length = 0;
creatOption(city,cityArr[province.value]);
if(province.value >= 0){
city.onchange();
}else{
country.options.length = 0;
}
};
var country = document.getElementById("country");
city.onchange = function(){
country.options.length = 0;
creatOption(country,countryArr[province.value][city.value]);
};
</script>
</body>
</html>
city.onchange = function(){
country.options.length = 0;
creatOption(country,countryArr[province.value][city.value]);
};
</script>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<script>
var arr = [1,2,3,4,2,5,6,2,7,2];
var arr2 = arr.filter(function(item){
if(item != 2){
return true
}
})
console.log(arr2)
</script>
</body>
</html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<script>
var arr = [1,2,3,4,2,5,6,2,7,2];
var arr2 = arr.filter(function(item){
if(item != 2){
return true
}
})
console.log(arr2)
</script>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#div{
width: 400px;
height: 400px;
background-color:#ccc;
margin: 100px auto;
}
.add{
border: 10px double red;
}
</style>
</head>
<body>
<div id="div"></div>
<input type="button" value="change" id="change">
<script>
var btn = document.getElementById('change');
var div = document.getElementById('div')
btn.onclick = function(){
div.classList.add('add')
}
</script>
</body>
</html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#div{
width: 400px;
height: 400px;
background-color:#ccc;
margin: 100px auto;
}
.add{
border: 10px double red;
}
</style>
</head>
<body>
<div id="div"></div>
<input type="button" value="change" id="change">
<script>
var btn = document.getElementById('change');
var div = document.getElementById('div')
btn.onclick = function(){
div.classList.add('add')
}
</script>
</body>
</html>