允许链接与preg-replace

Question

I have this so far :

preg_replace("/[^a-zA-Z0-9\/!?\" \' :,.;><_ ]/", "", 
html_entity_decode($text, ENT_QUOTES));

It works well, if I use other string a part from links .How do i accept <script></script> <iframe> <a href=""></a> http:// https:// ?

Answer 1

I have done many projects with RegEx in the past, here is a few of my queries.

Match "Every" link on a page.

$links = preg_match_all('#(?:<a\s+.*?href=[\'"]([^\'"]+)[\'"]\s*?.*?>((?:\s*(?!<\s*\/\s*a\s*>).\s*)*)<\s*\/\s*a\s*>)#i',$html,$patterns);

 // $patterns[0] (array) will give you the full tag <a herf="" ...etc
 // $patterns[1] (array) will give you the urls

You should print_r($patterns) to be sure what the actual arrays look like and how you want to use them.

To match <script> tags (this actually finds full javascript blocks, which may not be exactly what you're asking), however you can modify the code some.

preg_match_all("#<\s*script[^>]*[^/]>(.*?)<\s*/\s*script\s*>#i",$html,$scripts); 

To match <iframe> you can use this function (matches "every" iframe tag within html)

function html_iframe_tags($str) 
{
    $iframes = array();
    $iframeSearch = preg_match_all('#(?:<iframe[^>]*)(?:(?:/>)|(?:>.*?</\s*iframe>))#i', $str, $rawiframes);
    if (count($rawiframes[0])<1) return false;

    for ($i = 0; $i < count($rawiframes[0]); $i++)
    {
        $iframes[$i]['tag'] = $rawiframes[0][$i];

        preg_match_all('/src="([^"]*)"/i',$iframes[$i]['tag'], $iframesrc);
        $iframes[$i]['src'] = (isset($iframesrc[1][0]) ? $iframesrc[1][0] : '');

        preg_match_all('/\swidth="([^"]*)"/i',$iframes[$i]['tag'], $iframewidth);
        $iframes[$i]['width'] = (isset($iframewidth[1][0]) ? $iframewidth[1][0] : '');

        preg_match_all('/\sheight="([^"]*)"/i',$iframes[$i]['tag'], $iframeheight);
        $iframes[$i]['height'] = (isset($iframeheight[1][0]) ? $iframeheight[1][0] : '');
    }

    return $iframes;
 }

Then print_r() the results and see how the array looks for your exact usage, this function actually determines more than your use such as width/height etc. But also includes the src of which you are looking for.

Hopefully this stuff can give you direction for your project.

Here is a website that has some reference to regex in html
http://www.the-art-of-web.com/php/parse-links/