正規表現に関する問題: 画像の幅を 100% に置き換える

正则问题 将图片宽度替换为100%
宽度不定的图片

$str = '<p><br></p><img style="width: 513px;" src="<br />http://xxxx/uploads/details/142163431741415.jpg"><img style="width: 513px;" src="<br />http://xxxx/uploads/details/14216343172321.jpg"><p><br></p>';

宽度替换为100%

$str = '<p><br></p><img style="width: 100%;" src="<br />http://xxxx/uploads/details/142163431741415.jpg"><img style="width: 100%;" src="<br />http://xxxx/uploads/details/14216343172321.jpg"><p><br></p>';

------解决思路----------------------

$str = '<p><br></p><img style="width: 513px;" src="<br />http://xxxx/uploads/details/142163431741415.jpg"><img style="width: 613px;" src="<br />http://xxxx/uploads/details/14216343172321.jpg"><p><br></p>';<br /><br />echo preg_replace('/(?<=style="width:).+?px;/i', '100%', $str);

e388a4556c0f65e1904146cc1a846bee0c6dc11e160d3b678d68754cc175188a94b3e26ee717c64999d7867364b1b4a3fb40025d8b81174d241c320823b8bb9564737b2d712a07e2f29b10055797e383e388a4556c0f65e1904146cc1a846bee0c6dc11e160d3b678d68754cc175188a94b3e26ee717c64999d7867364b1b4a3

------解决思路----------------------
这样呢

echo  preg_replace('/(?<=<img)(.+?)style="width\: .+?"/s', '$1style="width: 100%;"', $str);