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javascript settings print

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Release： 2023-05-17 18:07:38

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Javascript Setting Print

In Web applications, the printing function is often essential. Javascript provides a convenient way to set up printing to ensure the best user experience when the page is printed. In this article, we will introduce how to set up printing using Javascript, let’s find out together!

Set printing style

In practice, we need to ensure that the printed page style can best meet the user's needs. Unlike screen displays, printed styles need to be more detailed and clear. Through Javascript, we can easily set print styles to ensure that the printed content meets the user experience.

First, we need to use CSS for the print style. This approach is similar to using CSS to change the page style. For example, in the following example, we set the page font size and color for printing:

<!DOCTYPE html>
<html>
<head>
  <title>JavaScript Set Print Style</title>
  <style>
    @media print {
      body {
        font-size: 12px;
        color: #333;
      }
    }
  </style>
</head>
<body>
  <h1>Hello, World!</h1>
  <p>This is an example paragraph.</p>
</body>
</html>

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Here, we use the @media print directive to set the printing CSS. Note that there is a @media directive in this style to ensure that these styles are only suitable for printers and will not be displayed in browsers. We set the font-size to 12px and the color to #333. This will ensure that when the page is printed, the font size and colors are the same as they appear on the screen. The same technique can be applied to other styles, such as background color and outer margins.

Set the content of the printed page

In some cases, we need to hide certain content to simplify the printed page and ensure that only the most needed information is displayed. Using Javascript we can easily hide any element on the page.

The following Javascript code shows how to hide elements in the page:

function hideElements() {
  var elements = document.getElementsByTagName('div');

  for (var i=0; i<elements.length; i++) {
    elements[i].style.display = 'none';
  }
}

window.onload = hideElements;

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In this example, we first define a function called hideElements. In this function, we use the getElementsByTagName method to get all div elements in the page. We then use a for loop to loop through each div tag and set them to "none" using the style.display property, which will hide them. Finally, we bind this function to the window.onload event to ensure that this function is executed when the page loads.

Set the layout of the printed page

Sometimes, we need to ensure that the layout of the page content meets the requirements as much as possible when printing. Using Javascript, we can easily change the page layout to ensure that the printed content meets the user's needs.

The following Javascript code demonstrates how to set the layout of the printed page:

function setPrintLayout() {
  var style = document.createElement('style');
  style.innerHTML = '@page {size: A4 portrait;}';
  document.head.appendChild(style);
}

window.onload = setPrintLayout;

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Here, we define a function named setPrintLayout. In this function, we create a style element using the createElement method. Then, we use innerHTML to set the CSS style, "@page {size: A4 portrait;}". This will make the page layout to A4 size with the landscape setting set to "portrait" for printing. Finally, we add the style to the document header using the appendChild method and call this function when the page loads.

Summary

In this article, we introduced how to set up printing using Javascript. By setting print styles, hiding and laying out page elements, we can easily ensure that printed pages provide the best user experience. If you are developing a web application and need to provide printing functionality, using this simple Javascript technique may be useful.

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