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);
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;
}
};
var country = document.getElementById("country");
city.onchange = function(){
country.options.length = 0;
creatOption(country,countryArr[province.value][city.value]);
};
</script>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>移出数组arr中与2相等的元素，并生成一个新数组，不改变原数组。</title>
</head>
<body>
<script>
var arr = [1,2,3,4,2,5,6,2,7,2];
var str4 = arr.slice(1,2);
var str1 = arr.slice(4,5);
var str2 = arr.slice(7,8);
var str3 = arr.slice(9);
str = str1.concat(str2,str3,str4);
document.write("原数组arr：<br/>" + arr);
document.write("<br/>");
document.write("移出数组arr中与2相等的元素，并生成一个新数组str：<br/>" + str);
document.write("<br/>");
document.write("没有改变原数组arr：<br/>" + arr);
</script>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>编写函数实现单击change按钮，为div元素添加红色双线的边框。</title>
<style type="text/css">
div{
font-family: "Helvetica Neue",Helvetica,Arial,"Microsoft Yahei",sans-serif;
width: 600px;
text-align: center;
}
.haha{
margin-top: 20px;
margin-left: 250px;
font-size: 20px;
}
.haha:hover{
border: 3px solid purple;
}
</style>
</head>
<body>
<div id="joy"> <p>123456。</p>
</div>
<button class="haha" onclick="myFunction()">change</button>
<script type="text/javascript">
function myFunction(){
var Color = document.getElementById("joy");
Color.style.border = "3px double red";
Color.innerHTML = "<p>123456789</p>";
}
</script>
</body>
</html>
