regex从html、css和javascript中提取所有图像文件

有一种方法可以完成这项工作:

$input = <<<EOD
CSS:
ul li {
    list-style-image: url('data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7');
}

#insert { background-image: url('../img/insert.jpg'); }
#delete { background-image: url('../img/delete.png'); }

HTML:
<link rel="icon" sizes="192x192" href="touch-icon-192x192.png">
<img id="home" src="img/home.png" class="img-home">

JavaScript:
"BackgroundImageUrl": "textures/glass.jpg"
EOD;

preg_match_all('/(?<=["\'])[^"\']+?\.(?:jpe?g|png|gif)(?=["\'])/', $input, $m);
print_r($m);

输出:

Array
(
    [0] => Array
        (
            [0] => ../img/insert.jpg
            [1] => ../img/delete.png
            [2] => touch-icon-192x192.png
            [3] => img/home.png
            [4] => textures/glass.jpg
        )

)

说明:

(?<=["\'])          : lookbehind, make sure we have a quote before
[^"\']+?            : 1 or more any character that is not a quote
\.                  : a dot
(?:jpe?g|png|gif)   : non capture group, list of image extensions
(?=["\'])           : lookahead, make sure we have a quote after