Analysis: Five common application scenarios of JS caching mechanism, reading content not to be missed

Must read: Analysis of five common application scenarios of JS caching mechanism

In Web development, caching is one of the important means to improve performance and reduce server load. In JavaScript, we can use the caching mechanism to improve web page loading speed and reduce network requests. This article will introduce five common application scenarios of the JS caching mechanism and provide specific code examples.

1. Static resource caching
Static resources include images, CSS files, JavaScript files, etc. The browser will cache these resources the first time they are requested. The next time you visit the same web page, the browser will read these resources directly from the cache without sending a network request. This can significantly reduce network overhead.

Code sample:

// 设置图片缓存
var img = new Image();
img.src = 'image.jpg';

// 设置CSS文件缓存
<link rel="stylesheet" href="style.css">

2. Data caching
In front-end development, sometimes we will obtain a large amount of data from the back-end. If we request the server every time, it will increase load on the server and slow down web page loading. Caching data on the front end can improve the response speed of the page.

Code example:

// 向服务器请求数据
$.ajax({
  url: 'data.php',
  success: function(data) {
    // 将数据缓存到LocalStorage中
    localStorage.setItem('data', JSON.stringify(data));
  }
});

// 从缓存中读取数据
var data = localStorage.getItem('data');
if (data) {
  // 解析缓存数据
  var jsonData = JSON.parse(data);
  // 使用缓存数据进行页面渲染
  renderPage(jsonData);
}

3. Page fragment caching
For some stable page fragments, we can cache them and obtain them directly from the cache when accessing again. No more duplication of generation and rendering. This can save a lot of rendering time and improve web page loading speed.

Code example:

// 判断本地是否有缓存
if (localStorage.getItem('fragment')) {
  // 直接从缓存中获取页面片段
  var fragment = localStorage.getItem('fragment');
  // 在页面中插入缓存的页面片段
  $('#container').html(fragment);
} else {
  // 从服务器请求并生成页面片段
  $.ajax({
    url: 'fragment.php',
    success: function(data) {
      // 将页面片段缓存到LocalStorage中
      localStorage.setItem('fragment', data);
      // 在页面中插入页面片段
      $('#container').html(data);
    }
  });
}

4. AJAX request caching
When using AJAX requests to obtain data, sometimes we hope that the data of the same URL will only be requested once, and the cache will be used directly for subsequent visits. data to avoid wasting time and bandwidth with repeated requests.

Code sample:

// 使用AJAX请求数据
$.ajax({
  url: 'data.php',
  cache: true, // 开启缓存
  success: function(data) {
    // 使用返回的数据进行页面渲染
    renderPage(data);
  }
});

5. Form data caching
For some commonly used form data, you can cache it locally and read it directly from the cache the next time you fill in the form. Improve user experience.

Code example:

// 判断本地是否有缓存
if (localStorage.getItem('formData')) {
  // 从缓存中获取表单数据
  var formData = JSON.parse(localStorage.getItem('formData'));
  // 填充表单
  $('#name').val(formData.name);
  $('#email').val(formData.email);
  $('#phone').val(formData.phone);
}

// 表单提交时保存数据到缓存
$('form').submit(function() {
  var formData = {
    name: $('#name').val(),
    email: $('#email').val(),
    phone: $('#phone').val()
  };
  // 将表单数据缓存到LocalStorage中
  localStorage.setItem('formData', JSON.stringify(formData));
});

In summary, the JS caching mechanism is very important in Web development. By properly utilizing cache, we can increase web page loading speed, reduce server load, and improve user experience. I hope this article can help readers better understand and apply the JS caching mechanism.

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