正则表达式使用php查找字符串中的确切部分

What should I use as a regex in order to get just the text between the double qoutes after url=

  <div class="anc-style" 
       url="c2l0ZT1odHRwJTNBJTJGJTJGZWFzeXJvdGF0b3IuY29tJTJGNjE1OTYlMkYmc2VjP TE1MjIzMyZsZW5nPWV4dGUmYWQ9MmM5ZTE5YjhiZWRiNzI1N2MxZGU2ODA2 Mjk0ZGZiYzcmYWQyPTAmYWQzPTAmYWQ0PTM=">

You regexp would be

$string = "your string here";

echo urldecode(base64_decode(preg_replace('/^.*url="(.*)".*$/', '$1', $string)));

If that's the url you want, I added base64_decode, and then urldecode since the result contained urlencoded characters.

Also I stongly suggest you learn regex basics if you'll be needing other search and replace!