Plug.php Simple seo plugin of BornoCMS

<?php
/*
    Plugin Name : Simple Seo Plugin
    Author : Arnob Protim Roy
    Detail : SImple Seo is a meta tag plugin
*/


if(!is_admin()){ // if it is not admin panel

    if(is_single()){ // if it is a single / content page than use content to short description

        $description = get_the_post($_GET['p'],'content');

        if(strlen($description)<160){
            $short_description= $description ;
        }else{
            $short_description  = the_excerpt($description,160);
        }





    }else{ // add the site description

        $short_description = get_the_option('site_description');

    }

    //strip all html tag from $short_description
    $short_description = strip_tags($short_description);

    // seo meta description tag tag
    $tag = "<meta name='description' content='$short_description'>";

    // add that to header
    add_header($tag);
}