<?php
header("Content-Type: application/json");
if(isset($_POST['limit'])){
$limit = preg_replace('#[^0-9]#', '', $_POST['limit']);
require_once("connect_db.php");
$i = 0;
$jsonData = '{';
$sqlString = "SELECT * FROM tablename ORDER BY RAND() LIMIT $limit";
$query = mysqli_query($con, $sqlString) or die (mysqli_error());
while ($row = mysqli_fetch_array($query)) {
$i++;
$id = $row["id"];
$title = $row["title"];
$cd = $row["creationdate"];
$cd = strftime("%B %d, %Y", strtotime($cd));
$jsonData .= '"article'.$i.'":{ "id":"'.$id.'","title":"'.$title.'", "cd":"'.$cd.'" },';
}
$now = getdate();
$timestamp = $now[0];
$jsonData .= '"arbitrary":{"itemcount":'.$i.', "returntime":"'.$timestamp.'"}';
$jsonData .= '}';
echo $jsonData;
}
?>
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
var myTimer;
function ajax_json_data(){
var databox = document.getElementById("databox");
var arbitrarybox = document.getElementById("arbitrarybox");
var hr = new XMLHttpRequest();
hr.open("POST", "json_mysql_data.php", true);
hr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
hr.onreadystatechange = function() {
if(hr.readyState == 4 && hr.status == 200) {
var d = JSON.parse(hr.responseText);
arbitrarybox.innerHTML = d.arbitrary.returntime;
databox.innerHTML = "";
for(var o in d){
if(d[o].title){
databox.innerHTML += '<p><a href="page.php?id='+d[o].id+'">'+d[o].title+'</a><br>';
databox.innerHTML += ''+d[o].cd+'</p>';
}
}
}
}
hr.send("limit=4");
databox.innerHTML = "requesting...";
myTimer = setTimeout('ajax_json_data()',6000);
}
</script>
</head>
<body>
<h2>Timed JSON Data Request Random Items Script</h2>
<div id="databox"></div>
<div id="arbitrarybox"></div>
<script type="text/javascript">ajax_json_data();</script>
</body>
</html>
PHP代码在一个名为“json_mysql_data.php”的单独文件中。我只是从https://www.youtube.com/watch?v=-Bv8P5oQnFw开始学习这个教程,它适用于他,但不适合我。我用mysql单独测试了“connect_db.php”,它运行正常。在我看来像php不会通过if(isset($ _POST ['limit']))但为什么...在html文件中我从javascript代码获得“请求...”消息,这意味着是等待PHP。谢谢你的帮助。
答案 0 :(得分:1)
您检查就绪状态,并使用databox
函数内的响应JSON 更改onreadystatechange
的内容:
hr.onreadystatechange = function(aEvt) {
if(hr.readyState == 4 && hr.status == 200) {
…
databox.innerHTML += …;
…
}
…
databox.innerHTML = "requesting...";
…
}
但是你改变了databox
:
databox.innerHTML = "requesting...";
仍然内部 onreadystatechange
功能的阻止 后会收到回复,因此databox
将始终说"requesting..."
无论你收到什么。您必须移动在其外部打印"requesting..."
的部分:
hr.onreadystatechange = function(aEvt) {
if(hr.readyState == 4 && hr.status == 200) {
…
databox.innerHTML += …;
…
}
…
}
…
databox.innerHTML = "requesting...";
…
<强>更新强>:
此外,您的功能似乎未正确定义,如您所见,MDN reference pages示例中的功能会收到参数:
req.onreadystatechange = function(aEvt) {
…
}
但你的没有这样的参数:
hr.onreadystatechange = function() {
…
}
答案就是这样。
答案 1 :(得分:0)
感谢您的帮助@arielnmz。我发现了这个问题。 PHP遇到getDate()
函数问题,因为PHP.ini文件中未配置date.timezone
字段。将以下行添加到文件中可以解决问题:
date.timezone = "UTC"