跳转到帖子
在手机APP中查看

一个更好的浏览方法。了解更多

OKCCN - XenForo & IPS Plugin Marketplace

主屏幕上的全屏APP,带有推送通知、徽章等。

在iOS和iPadOS上安装此APP
  1. 在Safari中轻敲分享图标
  2. 滚动菜单并轻敲添加到主屏幕
  3. 轻敲右上角的添加按钮。
在安卓上安装此APP
  1. 轻敲浏览器右上角的三个点菜单 (⋮) 。
  2. 轻敲添加到主屏幕安装APP
  3. 轻敲安装进行确认。
  • 选择语言

HTML Server-Sent Events API

推荐的帖子

  • 行政经理

HTML Server-Sent Events API


The Server-Sent Events (SSE) API enables pushing messages/updates from a server to the web page via HTTP connection.


Server-Sent Events - One Way Messaging

A server-sent event is when a web page automatically gets messages/updates from a server.

Normally, a web page has to request data from the server, but with server-sent events, the updates are pushed automatically.

Examples: Facebook/Twitter updates, stock market updates, news feeds, sport results, etc.


Browser Support

The numbers in the table specify the first browser version that fully support the Server-Sent Events API.

API
SSE 6.0 79.0 6.0 5.0 11.5

Receive Server-Sent Event Notifications

The EventSource object is used to receive server-sent event notifications:

Example

<script>
const x = document.getElementById("result");
// Check browser support for SSE
if(typeof(EventSource) !== "undefined") {
  var source = new EventSource("demo_sse.php");
  source.onmessage = function(event) {
    x.innerHTML += event.data + "<br>";
  };
} else {
  x.innerHTML = "Sorry, no support for server-sent events.";
}
</script>

Example explained:

  • Create a new EventSource object, and specify the URL of the page sending the updates (in this example "demo_sse.php")
  • Each time an update is received, the onmessage event occurs
  • When an onmessage event occurs, put the received data into the element with id="result"

Check Browser Support

In the tryit example above there were some extra lines of code to check browser support for server-sent events:

if(typeof(EventSource) !== "undefined") {
  // Yes! Server-sent events support!
  // Some code.....
} else {
  // Sorry! No server-sent events support..
}


Server-Side Code Example

For the example above to work, you need a server capable of sending data updates (like PHP or ASP).

The server-side event stream syntax is simple. Set the "Content-Type" header to "text/event-stream". Now you can start sending event streams.

Code in PHP (demo_sse.php):

<?php
header('Content-Type: text/event-stream');
header('Cache-Control: no-cache');

$time = date('r');
echo "data: The server time is: {$time}\n\n";
flush();
?>

Code in ASP (VB) (demo_sse.asp):

<%
Response.ContentType = "text/event-stream"
Response.Expires = -1
Response.Write("data: The server time is: " & now())
Response.Flush()
%>

Code explained:

  • Set the "Content-Type" header to "text/event-stream"
  • Specify that the page should not cache
  • Output the data to send (Always start with "data: ")
  • Flush the output data back to the web page

The EventSource Object

In the examples above we used the onmessage event to get messages. But other events are also available:

Events Description
onopen When a connection to the server is opened
onmessage When a message is received
onerror When an error occurs

参与讨论

你可立刻发布并稍后注册。 如果你有帐户,立刻登录发布帖子。

游客
回帖…

帐户

导航

搜索

搜索

配置浏览器推送通知

Chrome (安卓)
  1. 轻敲地址栏旁的锁形图标。
  2. 轻敲权限 → 通知。
  3. 调整你的偏好。
Chrome (台式电脑)
  1. 点击地址栏中的挂锁图标。
  2. 选择网站设置。
  3. 找到通知选项并调整你的偏好。