How to check if there is a string in the page URL

How do I check if there is a string in the page URL?
In view of the security, want to get the URL of this page, check if there is a "script" this string, if any, access or exit is forbidden. How to do it?

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Strstr Strpos
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You should has a HTML parser ...
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You should has a HTML parser. I Suppose there is such PHP version in the wild.
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PHP Code

  function Curpageurl () {    $pageURL = ' http ';    if ($_server["HTTPS"] = = "on")    {        $pageURL. = "S";    }    $pageURL. = "://";    if ($_server["Server_port"]! = "+")    {        $pageURL. = $_server["SERVER_NAME"]. ":" . $_server["Server_port"]. $_server["Request_uri"];    }    else    {        $pageURL. = $_server["SERVER_NAME"]. $_server["Request_uri"];    }    
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