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JavaScript端:
注意:一定要设置xmlHttp.setRequestHeader,否则传往PHP的参数会变成null(line 38)
亮点在line 31!- <script type="text/javascript">
- function GetJson() {
- var xmlHttp;
- try {
- // Firefox, Opera 8.0+, Safari
- xmlHttp = new XMLHttpRequest();
- }
- catch (e) {
- // Internet Explorer
- try {
- xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
- }
- catch (e) {
-
- try {
- xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
- }
- catch (e) {
- alert("您的浏览器不支持AJAX!");
- return false;
- }
- }
- }
-
- xmlHttp.onreadystatechange = function() {
- if (xmlHttp.readyState == 4) {
- //alert(xmlHttp.responseText);
- var str = xmlHttp.responseText;
- document.getElementById('show').innerHTML +=str;
- //alert(str);
- var obj = eval('('+ xmlHttp.responseText +')');
- //var obj = eval(({"id":"123","name":"elar","age":"21"}));
- alert(obj.name);
- }
- }
- var data = "id=123";
- xmlHttp.open("POST", "testJson.php", true);
- xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
- xmlHttp.send("id=123");
- }
- </script>
- <input type="button" onclick="GetJson()" value="按我!"/>
- <hr />
- <div id="show"></div>
复制代码 PHP端【testJson.php】:
(注意,php文件要干净,<?php ?>标签的外部不能有其他标签,否则eval函数无法解析)
亮点在line 6- <?php
- $res['id'] = $_POST['id'];
- $res['name'] = "elar";
- $res['age'] = "21";
- $response = "hello this is response".$_POST['id'];
- echo json_encode($res);
- ?>
复制代码 总结:
js要往PHP端送数据,用的是xmlHttp.send("id=123");
PHP给js送数据,用的是echo json_encode($res);(要注意变量$res的构造应符合JSON的规范)
js要解析PHP送来的JSON格式的数据,用var obj = eval('('+ xmlHttp.responseText +')'); |
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