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The difference between front-end and back-end event dispatching mechanisms in PHP

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Release： 2023-07-10 20:24:01

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The difference between front-end and back-end event dispatch mechanisms in PHP

When developing web applications, front-end and back-end event triggering and processing are very important parts. In PHP, there are some differences between front-end and back-end event dispatching mechanisms, and understanding these differences is crucial to developing efficient applications. This article will introduce the difference between front-end and back-end event dispatching mechanisms in PHP and explain it through code examples.

The front-end event dispatch mechanism is triggered when the user interacts with the front-end interface. These events can be user actions such as clicks, inputs, and drags. The front-end event dispatching mechanism will send the event to the target element of the event, and then pass it along the DOM tree to the parent element until it reaches the document root node. During the event delivery process, each target element or parent element has the opportunity to process the event or prevent the event from being delivered.

The following is a simple front-end event dispatch example:

<!DOCTYPE html>
<html>
<head>
  <script>
    function handleClick(event) {
      alert("按钮被点击了！");
    }
  </script>
</head>
<body>
  <button onclick="handleClick(event)">点击我</button>
</body>
</html>

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In the above code, when the user clicks the button, the handleClick function will be triggered and a message box will pop up.

In contrast, the back-end event dispatch mechanism is processed on the server. When the client requests a URL, the server receives the request and triggers the corresponding event. The triggering of the back-end event dispatch mechanism is controlled by the server, unlike front-end events which are triggered by user behavior.

The following is a simple example of back-end event dispatch:

<?php
  $url = $_SERVER['REQUEST_URI'];
  
  if ($url == '/login') {
    loginUser();
  } elseif ($url == '/register') {
    registerUser();
  } else {
    notFoundPage();
  }
  
  function loginUser() {
    echo "用户登录处理逻辑";
  }
  
  function registerUser() {
    echo "用户注册处理逻辑";
  }
  
  function notFoundPage() {
    echo "页面未找到";
  }
?>

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In the above code, when the user requests a different URL, the server will trigger the corresponding event processing function based on the requested URL. .

An important difference between the front-end and back-end event dispatch mechanisms is the different processing locations of events. The front-end event dispatching mechanism places the event processing logic in the browser, while the back-end event dispatching mechanism places the event processing logic in the server.

Another difference is the flexibility of event handling. Since front-end events are triggered by user behaviors, events can be processed based on different user behaviors, such as clicks, drags, inputs, etc. Back-end events rely more on server-side logic and request parameters, and the processing of events is relatively fixed.

In summary, there is a clear difference between the front-end event dispatching mechanism and the back-end event dispatching mechanism in PHP. The front-end event dispatch mechanism is triggered when the user interacts with the front-end interface, and the event processing logic is completed in the browser; while the back-end event dispatch mechanism is processed on the server side, and the server triggers the corresponding event processing function according to the request. Understanding these differences is crucial to developing efficient web applications.

References:

https://www.w3schools.com/js/js_events.asp
https://www.php.net/manual /en/language.variables.superglobals.php

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