AjaxJavaScript天气预报php天气预报，用php来写一个天气预报的模块。
天气数据是通过采集中国气象网站的。本来中国天气网站也给出了数据的API接口。以下是API的地址。返回的数据格式为json格式。
1. http://www.weather.com.cn/data/sk/101010100.html
2. http://www.weather.com.cn/data/cityinfo/101010100.html
3. http://m.weather.com.cn/data/101010100.html
URL中的数字”101010100“是城市代码。所以可以先列出每个城市的城市代码，然后php程序接收到了城市代码，再去组装URL，在通过URL来显示该城市的实时天气。
index.php
<?php
header("Content-Type:text/html;charset=utf-8");
?>
<html>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<head>
<title>weather forecast天气预报--www.jbxue.com</title>
<script type="text/javascript" src="ajax.js"></script>
<script type="text/javascript">
function $(id){
return document.getElementById(id);
}
function getCityId(){
var http_request=createAjax();
var url="weatherforecast.php"
var data="cityid="+$("cityId").value;
http_request.onreadystatechange=getWetherInfo;
http_request.open("post",url,true);
http_request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
http_request.send(data);
function getWetherInfo(){
if(http_request.readyState==4 && http_request.status==200){
var info=http_request.responseText;
$("weatherinfo").innerHTML=info;
}
}
}
</script>
</head>
<body>
<select name="cityId" onchange="getCityId();" id="cityId">
<option>--请选择城市--</option>
<option value="101010100">北京</option>
<option value="101020100">上海</option>
<option value="101030100">天津</option>
<option value="101040100">重庆</option>
<option value="101280101">广州</option>
</select>
<span id="weatherinfo"></span>
</body> </html>
header("Content-Type:text/html;charset=utf-8");
?>
<html>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<head>
<title>weather forecast天气预报--www.jbxue.com</title>
<script type="text/javascript" src="ajax.js"></script>
<script type="text/javascript">
function $(id){
return document.getElementById(id);
}
function getCityId(){
var http_request=createAjax();
var url="weatherforecast.php"
var data="cityid="+$("cityId").value;
http_request.onreadystatechange=getWetherInfo;
http_request.open("post",url,true);
http_request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
http_request.send(data);
function getWetherInfo(){
if(http_request.readyState==4 && http_request.status==200){
var info=http_request.responseText;
$("weatherinfo").innerHTML=info;
}
}
}
</script>
</head>
<body>
<select name="cityId" onchange="getCityId();" id="cityId">
<option>--请选择城市--</option>
<option value="101010100">北京</option>
<option value="101020100">上海</option>
<option value="101030100">天津</option>
<option value="101040100">重庆</option>
<option value="101280101">广州</option>
</select>
<span id="weatherinfo"></span>
</body> </html>
weatherforecast.php
<?php
header("Content-Type:text/html;charset=utf-8");
header("Cache-Control:no-cache");
if (isset($_POST['cityid'])){
$cityid=$_POST['cityid'];
$url=$url="http://www.weather.com.cn/data/sk/".$cityid.".html";
}else {
$url="http://www.weather.com.cn/data/sk/101010100.html";
}
$weatherInfo_json=file_get_contents($url);
$weatherInfo=json_decode($weatherInfo_json,true);
$cityName=$weatherInfo['weatherinfo']['city'];
$cityTemp=$weatherInfo['weatherinfo']['temp'];
$cityWd=$weatherInfo['weatherinfo']['WD'];
$cityWs=$weatherInfo['weatherinfo']['WS'];
$cityTime=$weatherInfo['weatherinfo']['time'];
$citySD=$weatherInfo['weatherinfo']['SD'];
echo $weatherinfo="城市名字：$cityName,气温：$cityTemp,风向：$cityWd";
?>
header("Content-Type:text/html;charset=utf-8");
header("Cache-Control:no-cache");
if (isset($_POST['cityid'])){
$cityid=$_POST['cityid'];
$url=$url="http://www.weather.com.cn/data/sk/".$cityid.".html";
}else {
$url="http://www.weather.com.cn/data/sk/101010100.html";
}
$weatherInfo_json=file_get_contents($url);
$weatherInfo=json_decode($weatherInfo_json,true);
$cityName=$weatherInfo['weatherinfo']['city'];
$cityTemp=$weatherInfo['weatherinfo']['temp'];
$cityWd=$weatherInfo['weatherinfo']['WD'];
$cityWs=$weatherInfo['weatherinfo']['WS'];
$cityTime=$weatherInfo['weatherinfo']['time'];
$citySD=$weatherInfo['weatherinfo']['SD'];
echo $weatherinfo="城市名字：$cityName,气温：$cityTemp,风向：$cityWd";
?>