for...in语句解析
<script>
var json={a: 12, b: 5};
for(var i in json)
{
alert(i+'='+json[i]);
}
</script>eval() 函数可计算某个字符串, 并执行其中的的 JavaScript 代码。
服务器端脚本代码：
<?php
$row=array('username'=>'lisi','password'=>'222222');
echo json_encode($row);
/*$data=array(
array('name'=>'zhangsan','age'=>18),
array('name'=>'lisi','age'=>30)
);
echo json_encode($data);
*/
?>var json=eval('('+value+')'); 主要是针对关联数组
返回："{name:'zhangsan',age:18}"
访问方式:json.username+json.password
var json=eval(value); 主要是针对索引数组
返回："[{name:'zhangsan',age:18},{name:'lisi',age:20}]"
访问方式:json[0].name+json[0].age
注意：索引数组的解析也可以采用 var json=eval(value);
<script language="javascript" src="public.js"></script>
<script>
var xhr=createxhr(); //创建ajax对象, 代码见ajax | ajax封装GET和POST
xhr.open('post','demo05.php');
xhr.setRequestHeader('Content-type','application/x-www-form-urlencoded');
xhr.onreadystatechange=function(){
if(xhr.readyState==4 && xhr.status==200){
var value=xhr.responseText; //返回的是字符串
//1)
var json=eval('('+value+')'); //返回是json对象
alert(json.username+json.password);
//2)
//var json=eval(value); //返回是json数组对象
//alert(json[1].name+json[1].age);
}
};
xhr.send(null);
</script>返回："{name:’zhangsan’,age:18}"
解析格式：eval('('+value+')');
返回："[{name:'zhangsan',age:18},{name:'lisi',age:20}]"
解析格式：eval(value);
也可以采用eval('('+value+')');
实例1:
<html>
<head>
<title>新建网页</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="description" content="" />
<meta name="keywords" content="" />
<script type="text/javascript">
function f1(){
//ajax去服务器获得json信息
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function(){
if(xhr.readyState==4 && xhr.status==200){
//alert(xhr.responseText);//字符串{"north":"wolf","helan":"pig","germany":"dog"}
var info = eval('('+xhr.responseText+')');
//也可写成：eval("var info="+xhr.responseText);
document.write(info.north);
document.write(info.helan);
document.write(info.germany);
}
}
xhr.open('get','03.php');
xhr.send(null);
}
//javascript把一个字符串变为对象
//var a = '{"north":"wolf","helan":"pig","germany":"dog"}';
//eval(参数字符串)
//eval("var obj="+a);//eval('var obj={"north":"wolf","helan":"pig","germany":"dog"}');
//document.write(obj);//访问对象
</script>
</head>
<body>
<h2>静态网站，javascript对json的接收处理</h2>
<input type="button" value="触发" onclick="f1()" />
</body>
</html>
<?php
//对外提供json信息
header("Cache-Control:no-cache,must-revalidate");
$animal = array('north'=>'wolf','helan'=>'pig','germany'=>'dog');
echo json_encode($animal); //{"north":"wolf","helan":"pig","germany":"dog"}
?>在javascript解析{"north":"wolf","helan":"pig","germany":"dog"}
采用：var info = eval('('+xhr.responseText+')'); 语法
也可写成：eval("var info="+xhr.responseText);
实例2：
<html>
<head>
<title>新建网页</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="description" content="" />
<meta name="keywords" content="" />
<script type="text/javascript">
function f1(){
//ajax去服务器获得json信息
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function(){
if(xhr.readyState==4 && xhr.status==200){
//alert(xhr.responseText);//数组 ["wolf","pig","dog"]
var info = eval(xhr.responseText);
document.write(info[0]+info[1]+info[2]);
}
}
xhr.open('get','03.php');
xhr.send(null);
}
</script>
</head>
<body>
<h2>静态网站，javascript对json的接收处理</h2>
<input type="button" value="触发" onclick="f1()" />
</body>
</html>
<?php
//对外提供json信息
header("Cache-Control:no-cache,must-revalidate");
$animal = array('wolf','pig','dog');
echo json_encode($animal); //["wolf","pig","dog"]
?>在javascript解析["wolf","pig","dog"]时
采用：var info = eval(xhr.responseText);语法
实例3:
<html>
<head>
<title>新建网页</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="description" content="" />
<meta name="keywords" content="" />
<script type="text/javascript">
function f1(){
//ajax去服务器获得json信息
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function(){
if(xhr.readyState==4 && xhr.status==200){
var s = "";
//alert(xhr.responseText);//数组对象[{"id":1,"name":"xutao","sex":"\u7537","age":30},...]
var info = eval(xhr.responseText);
for(var i=0;i<info.length;i++){
s += info[i].id + "--" + info[i].name + "--" + info[i].sex + "--" + info[i].age +"<br />";
}
document.getElementById("user").innerHTML = s;
}
}
xhr.open('get','info.php');
xhr.send(null);
}
</script>
</head>
<body>
<h2>静态网站，javascript对json的接收处理</h2>
<input type="button" value="触发" onclick="f1()" />
<div id="user"></div>
</body>
</html>
<?php
$info = array(
array("id"=>1,"name"=>"zhangsan","sex"=>"男","age"=>30),
array("id"=>2,"name"=>"lisi","sex"=>"女","age"=>27),
array("id"=>3,"name"=>"wangwu","sex"=>"男","age"=>6)
);
echo json_encode($info);
/* [{"id":1,"name":"zhangsan","sex":"\u7537","age":30},
{"id":2,"name":"lisi","sex":"\u5973","age":27},
{"id":3,"name":"wuwang","sex":"\u7537","age":6}] */
?>在javascript解析[{"id":1,"name":"zhangsan","sex":"\u7537","age":30},
{"id":2,"name":"lisi","sex":"\u5973","age":27},
{"id":3,"name":"wuwang","sex":"\u7537","age":6}]时
采用：var info = eval(xhr.responseText);语法
从数据库读取出来的二维数组，通过json_encode()编码后, 在javascript进行解析时也是采用上述语法。