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AJAX uses JSONP to achieve cross-domain data transfer

WBOYOriginal: 2016-08-08 09:29:20914browse

A while ago, I suddenly thought about completely removing some IFRAME calls on the website, so I wanted to use ajax+json to implement it, but later I found that the message "No 'Access-Control-Allow-Origin' header is present on the requested resource" error. Since ajax cannot cross domains, it is implemented in JSONP mode. It is very simple:

1. Client source code

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>test</title>
</head>

<body>
<script language="javascript" src="jquery-1.4.2.min.js"></script>
<script type="text/javascript">
$(function() {
		var url = "http://192.168.1.102/index_szxx_ajax.php";
		$.ajax({
		  type: "get",
          async: false,
		  url: url,
		  dataType: "jsonp",
		  jsonp: "callback",
		  jsonpCallback:"infolist",
		  success: function infolist(data){//数据返回后的处理函数infolist
			  var backdata="";
			  for(var a in data){
				  for(var b in data[a]){
					  backdata=backdata+data[a][b]+"<br>";	
				  }
			  }
			  $("#backdata").html(backdata);
		}
	  });
});

</script>
<div id="backdata">正在查询...</div>
</body>
</html>

2. Server-side source code index_szxx_ajax.php

<? require("inc/conn.php");?>
<?
$rows=array();

$sqlinfolist="select * from v_info where  info_state=1 and user_class=0 order by update_date desc limit 0,9";

$rs_listinfo=$db->query($sqlinfolist);
while(($r=$rs_listinfo->fetch_assoc())==true){
	$rows[]=$r;	
}
exit("infolist(".json_encode(gbk2utf8($rows)).");");//返回查询的JSON格式结果集并调用回调函数<span style="font-family: Arial, Helvetica, sans-serif;">infolist</span>


//服务器端数据库为gb2312编码，转为JSON格式必须为UTF-8编码否则有汉字的单元值会变成NULL;
function gbk2utf8($data){
    if(is_array($data)){
        return array_map('gbk2utf8', $data);
    }
    return iconv('gbk','utf-8',$data);
}
?>

The above introduces how AJAX uses JSONP to achieve cross-domain data transfer, including aspects of it. I hope it will be helpful to friends who are interested in PHP tutorials.

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