php过滤非本站链接

$str ='<li><a href="http://www.111cn.net/12345s" target="_blank"> 施华洛世奇！</a></li><li><a href=http://123.com/n.php?a=luxury& target="_blank"> f乔</a></li><li><a href="http://mb.111cn.net/" target="_blank"> f衣';

$match='/<li><ashref="?http://[w.]*123.com/[w]+.php?a=*[w&=]*"?s+target="_blank">(.*)</a></li>/isu';
preg_match_all($match,$str,$arr);
echo "<pre>";
print_r($arr[0]);
echo "</pre>";

<img style src="<?=$url?>/images/styleno.jpg" width="30" height="30" />
<img style src="<?=$url?>/images/styleno.jpg" width="30" height="30" />
<img src="images/styleno.jpg" width="30" height="30" />
<img src="images/styleno.jpg" width="30" height="30" />
想用正则把他们替换成
有 style的 替换成<img src="<?=$url?>/images/styleno.jpg" width="30" height="30" />
没style 的 替换成<img src="<?=$path?>/images/styleno.jpg" width="30" height="30" />

*/

$content1 ='<img style src="<?=$url?>/images/styleno.jpg" width="30" height="30" />';
$content ='<img style src="/images/styleno.jpg" width="30" height="30" />';
$a='<img src="<?=$url?>/images/styleno.jpg" width="30" height="30" />';
echo preg_replace('/<imgs+styles+src=['"]?[^'"]*['"]?\s+.*\/>/i',$a,$content);

$content1 ='<img src="images/styleno.jpg" width="30" height="30" />';
$b='<img src="<?=$path?>/images/styleno.jpg" width="30" height="30" />';
echo preg_replace('/<img src=['"]?[^'"]*['"]?\s+.*\/>/i',$b,$content1);

$arr_ip = array(
"127.0.0.1",
"218.206.10.123",
"192.221.515.0",
"123.0.0.0.1",
"-12.255.0.10",
"10.9c.132.69",
"255.10.10.255"
);

foreach ($arr_ip as $ip)
{
    if(validateip($ip))
    {
        echo "<b>$ip 是正确的ip地址</b>";
        echo "<br/><br/>";
    }
    else
    {
        echo "$ip 不是正确的ip地址";
        echo "<br/><br/>";
    }
}

function validateip($ip)
{
    $iparray = explode(".",$ip);
    for($i=0;$i<count($iparray);$i++)
    {
        if($iparray[$i]>255)
            return (0);
    }
    return ereg("[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}",$ip);
}
 // 检查ip地址的正则表达式示例2。
 $arr_ip = array(
"127.0.0.1",
"218.206.10.123",
"192.221.515.0",
"123.0.0.0.1",
"-12.255.0.10",
"10.9c.132.69",
"255.10.10.255"
);

foreach ($arr_ip as $ip)
{
    if(validateip($ip))
    {
        echo "<b>$ip 是正确的ip地址</b>";
        echo "<br/><br/>";
    }
    else
    {
        echo "$ip 不是正确的ip地址";
        echo "<br/><br/>";
    }
}

function validateip($ip)
{
    $iparray = explode(".",$ip);
    for($i=0;$i<count($iparray);$i++)
    {
        if($iparray[$i]>255)
            return (0);
    }
    return ereg("^[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}$",$ip);
}

 $str_arr = array(
"mymail@111cn.net",
"my_mail@111cn.net",
"my-mail@111cn.net",
"my.mail@site.com.cn",
"mymail@site.com.ccoomm",
"mymail@site.cn",
"mymail@@@lsite.com",
"mymail@site",
"mymail@111cn.net",
"my2007@111cn.net",
"163mail_for-me777@111cn.net",
);

$patt_email = "/^[_a-za-z0-9-]+@([0-9a-z][0-9a-z-]+.)+[a-z]{2,4}$/";

foreach ($str_arr as $str)
{
    echo "字符串'$str'：是";
    if (preg_match($patt_email, $str))
    {
        echo "<b>合法的email格式</b>";
        echo "<br>";
        echo "<br>";
    }
    else
    {
        echo "不合法的email格式";
        echo "<br>";
        echo "<br>";
    }
}
 

$str_arr = array(
"http://www.111cn.net",
"www.111cn.net",
"http://www.111cn.net/abc/123.html",
"//111cn.net",
":www.111cn.net"
);

$patt_url = "/^(http://)?[a-za-z0-9]+(.[a-za-z0-9]+)*.+$/";

foreach ($str_arr as $str)
{
    echo "字符串'$str'：是";
    if (preg_match($patt_url, $str))
    {
        echo "<b>合法的url格式</b>";
        echo "<br>";
        echo "<br>";
    }
    else
    {
        echo "不合法的url格式";
        echo "<br>";
        echo "<br>";
    }
}