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A multi-angle analysis of how CSS and PHP work together

PHPz

Release： 2023-04-25 13:51:31

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CSS is a styling language used to beautify web pages, while PHP is a scripting language used for web development. In the actual web development process, CSS and PHP are often inseparable. How can they work better together to make the web page more beautiful, dynamic and easy to maintain? This article will analyze how CSS and PHP work with each other from different perspectives.

1. The basis of the combination of CSS and PHP

1.1. Introduction of CSS styles

When using PHP to develop web pages, in order to facilitate maintenance and management, the web page is usually The header, tail, left navigation and other parts are separated into different files for management. These files are usually named with the .php suffix. However, the styling code for a web page is usually placed in a .css file. So, how to reference CSS styles in PHP files? The commonly used method is as follows:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>PHP与CSS结合</title>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <!-- 此处为 HTML 代码 -->
</body>
</html>

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In the HTML file, we use the <link> tag to reference the style.css file. This method is called the introduction method of external style sheets. . This method not only makes it easier for developers to manage CSS styles, but also makes web page downloads faster and improves user experience.

1.2. PHP controls the output of HTML tags

PHP provides some built-in functions that can be used to output HTML tags. For example, we want to display different content on the web page based on the user's gender. The code is implemented as follows:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>PHP与CSS结合</title>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <?php
        $gender = "male";
        if ($gender == "male") {
            echo "<span class=&#39;blue&#39;>男性用户</span>";
        } else {
            echo "<span class=&#39;pink&#39;>女性用户</span>";
        }
    ?>
</body>
</html>

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In the above example, we use PHP conditional statements to display different content based on the user's gender. content. It should be noted here that we used the  tag instead of the  or <div> tag because The  tag is usually used to style a small part of a web page, such as applying the style.css file mentioned above.

2. Practice of combining CSS styles with PHP

2.1. Dynamically modify CSS styles based on the results output by PHP

In the above example, we have used PHP control The output method of HTML tags, however, what if we need to dynamically modify the CSS styles of certain elements in the web page based on the output results of PHP? This allows developers to more easily control web page styles and enhance user experience.

The following is a case where the style of an element is dynamically modified based on the results output by PHP:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>PHP与CSS结合</title>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <?php
        $gender = "male";
        if ($gender == "male") {
            $color = "blue";
        } else {
            $color = "pink";
        }
    ?>

    <!-- 动态修改 p 标签的字体颜色 -->
    <p style="color:<?php echo $color;?>;">这是一个测试</p>
</body>
</html>

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Since PHP contains conditional statements, developers can output different values in PHP according to different situations. , and then substitute these values into CSS properties, so that the style of the element can be dynamically modified based on the PHP output results.

2.2. Calling PHP variables

During the web development process, some variables need to be temporarily stored for later use. Placing it in a separate PHP file can improve the maintainability of the code, but calling these variables in the PHP file requires the use of some special features in the external style sheet.

The following is an example of dynamically controlling the path of an image through PHP variables:

img {
    background-image: url('<?php echo $bg;?>" />
}

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In this example, we use <?php echo $bg;?> to call the PHP variable, which is assigned a path, which can help us control the display of images on the web page more conveniently.

3. Conclusion

From the above examples, we can find that CSS and PHP cooperate very closely. Whether you are applying an external style sheet, dynamically modifying the style of a markup element, or dynamically controlling the display of images, you must use the features of the PHP language. In actual work, developers need to be proficient in the basic knowledge of CSS and PHP, and combine their characteristics to give full play to their advantages to achieve more efficient, beautiful, and easy-to-maintain web page design and development purposes.

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