In CSS:visited privacy protection-CSS Tutorial-php.cn

In CSS:visited privacy protection

高洛峰

Release： 2017-02-22 12:59:32

Original

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CSS Pseudo-classes

Anchor pseudo-classes: In browsers that support CSS, different states of links can be displayed in different ways. These states include: active state, visited status, unvisited status, and mouseover status.

a:link {color: #FF0000} /* Unvisited link*/a:visited {color: #00FF00} /* Visited link*/a:hover {color: #FF00FF} / * Move the mouse to the link */a:active {color: #0000FF} /* Selected link */

The use of a tag often changes the style through pseudo-classes, such as hover The background background after the stop, font-size font size, text-decoration text style (none to remove underline), color font color, etc., but so many styles cannot be changed under :visited.

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
        <style type="text/css">
.fi:hover{
    text-decoration: none;
    color: green;
    font-size: 20px;
    background-color: red; 
    border: 1px solid black;
}
.se:visited{
    text-decoration: none;/*无效*/
    color: green;
    font-size: 20px;/*无效*/
    background-color: red; /*这个按理来说应该有效*/   
    border: 1px solid black;/*无效*/
}
        </style>
    </head>
    <body>
        <a href="#qwe" class="fi">123465</a><br />
        <a href="#aasd" class="se">7890</a>
    </body>
</html>

Copy after login

Many years ago, CSS:visited was a way to query user history. It had no threat on its own, but when it is combined with getComputedStyle() in js, it can pass your history Logging finds where you've been. The speed can reach 210,000 URLs per minute, so it is possible to obtain a large amount of your historical information or copy your identity through fingerprint printing. Since browsers can store history for long periods of time, this method can expose a significant portion of your browsing information.

Wow, those awesome people don’t want others to see where they download resources every day, so they started to protect the privacy of users. Well, they do.

Change the getComputedStyle method to always return values as if the user has never visited this website. (But I haven’t tried what this is.)

The :visited castration can only be used to modify color, background-color, border-*-color, outline-color, and some fill and stroke attribute, other attributes are replaced by :link. And you cannot use rgba(), hsla(), and transparent colors.

If there are any errors in the translation, please feel free to slap me in the face.

For more CSS:visited privacy protection related articles, please pay attention to the PHP Chinese website!