正则替换请教！
<div class="login float-r">
<a class="float-l" href="http://local.ldnew.com/index.php?option=com_virtuemart&page=shop.registration" title="Sign Up">Sign Up </a>
<span class="float-l">|</span>
<a class="float-l" href="http://local.ldnew.com/index.php?option=com_user&view=login&return=aHR0cDovL2xvY2FsLmxkbmV3LmNvbS8/bGRrZXk9YXB1dHVyZQ==" title="Login">Login</a>
</div>

如何将上面<div class="login float-r"> ****** </div> 中间的部分用正则替换成<?echo $_COOKIE['username'];?>

------解决方案--------------------
中间不含div的话

$str = preg_replace("/<div class=\"login float-r\">.*<\/div>/ims","<div class=\"login float-r\"><\?echo \$_COOKIE['username']\;\?><\/div>",$str);

自己测试一下
------解决方案--------------------
$str = preg_replace("/<div class=\"login float-r\">.*<\/div>/ims",'<div class="login float-r"><?echo $_COOKIE[\'username\'];?></div>',$str);
------解决方案--------------------

探讨

$str = preg_replace("/<div class=\"login float-r\">.*<\/div>/ims",'<div class="login float-r"><?echo $_COOKIE[\'username\'];?></div>',$str);