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Using JavaScript to implement page zoom function

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Aug 09, 2023 am 10:06 AM

javascript page zoom

Using JavaScript to implement page zoom function

Use JavaScript to implement page zoom function

In modern web design, user experience is a crucial part. In order to adapt to the needs of users of different devices and screen sizes, we often need to scale the page. Today, we will use JavaScript to implement the page zoom function.

The scaling function of HTML is implemented in CSS by setting the viewport. However, sometimes we need to dynamically scale the page to adjust according to the user's operations. At this time, we can use JavaScript to implement the page zoom function.

First, we need to add a button to the HTML file to trigger the zoom operation of the page. The code is as follows:

<button onclick="zoomIn()">放大</button>
<button onclick="zoomOut()">缩小</button>

Next, we need to write JavaScript code to implement the zoom function. The code is as follows:

// 获取当前页面的缩放比例
function getZoom() {
  return parseFloat(document.body.style.zoom) || 1;
}

// 设置页面的缩放比例
function setZoom(zoom) {
  document.body.style.zoom = zoom;
}

// 页面放大函数
function zoomIn() {
  var zoom = getZoom();
  setZoom(zoom + 0.1);
}

// 页面缩小函数
function zoomOut() {
  var zoom = getZoom();
  if (zoom > 0.2) {
    setZoom(zoom - 0.1);
  }
}

In the above code, we defined four functions: getZoom is used to obtain the zoom ratio of the current page, setZoom is used to set the zoom ratio of the page, zoomIn is used to zoom in on the page, and zoomOut is used to to shrink the page. The specific implementation principle is to achieve zooming by modifying the zoom style of the page.

Finally, we only need to embed the JavaScript code into the <script></script> tag of the HTML file. The complete code is as follows:

<!DOCTYPE html>
<html>
<head>
  <title>页面缩放功能</title>
  <style>
    body {
      margin: 0;
      padding: 0;
    }
  </style>
</head>
<body>
  <h1 id="页面缩放功能示例">页面缩放功能示例</h1>
  <button onclick="zoomIn()">放大</button>
  <button onclick="zoomOut()">缩小</button>

  <script>
    function getZoom() {
      return parseFloat(document.body.style.zoom) || 1;
    }

    function setZoom(zoom) {
      document.body.style.zoom = zoom;
    }

    function zoomIn() {
      var zoom = getZoom();
      setZoom(zoom + 0.1);
    }

    function zoomOut() {
      var zoom = getZoom();
      if (zoom > 0.2) {
        setZoom(zoom - 0.1);
      }
    }
  </script>
</body>
</html>

Now, we have completed the code that uses JavaScript to implement the page zoom function. When the user clicks the zoom-in button on the page, the page will be zoomed in 0.1 times, and when the user clicks the zoom-out button, the page will be zoomed out 0.1 times. In this way, users can adjust the display effect of the page according to their own needs.

To sum up, using JavaScript to implement the page zoom function is a very simple and flexible method. Through simple code, we can implement user-friendly page zoom operations and improve the user experience of web pages. Hope this article can help you!

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