php有什么用

php是一个嵌套的缩写名称，是英文超级文本预处理语言，它的语法混合了C、Java、Perl以及php自创新的语法，主要用来做网站开发，许多小型网站都用php开发，因为php是开源的，从而使得php经久不衰。

PHP RSS 生成类实例代码如下:

if (defined('_class_rss_php')) return;
define('_class_rss_php教程',1);
 
class rss {
   //public
   $rss_ver = "2.0";
   $channel_title = '';
   $channel_link = '';
   $channel_description = '';
   $language = 'zh_cn';
   $copyright = '';
   $webmaster = '';
   $pubdate = '';
   $lastbuilddate = '';
   $generator = 'redfox rss generator';
 
   $content = '';
   $items = array();
 
   function rss($title, $link, $description) {
       $this->channel_title = $title;
       $this->channel_link = $link;
       $this->channel_description = $description;
       $this->pubdate = date('y-m-d h:i:s',time());
       $this->lastbuilddate = date('y-m-d h:i:s',time());
   }
 
   function additem($title, $link, $description ,$pubdate) {
       $this->items[] = array('titile' => $title ,
                        'link' => $link,
                        'description' => $description,
                        'pubdate' => $pubdate);
   }
 
   function buildrss() {
       $s = " ";
       // start channel
       $s .= " ";
       $s .= " "
       $s .= "{$this->channel_link} ";
       $s .= "{$this->channel_description} ";
       $s .= "{$this->language} ";
       if (!emptyempty($this->copyright)) {
          $s .= "{$this->copyright} ";
       }
       if (!emptyempty($this->webmaster)) {
          $s .= "{$this->webmaster} ";
       }
       if (!emptyempty($this->pubdate)) {
          $s .= "{$this->pubdate} ";
       }
 
       if (!emptyempty($this->lastbuilddate)) {
          $s .= "{$this->lastbuilddate} ";
       }
 
       if (!emptyempty($this->generator)) {
          $s .= "{$this->generator} ";
       }
      
       // start items
       for ($i=0;$iitems),$i++) {
           $s .= " ";
           $s .= " ";
           $s .= "{$this->items[$i]['link']} ";
           $s .= "items[$i]['description']}]]> ";
           $s .= "{$this->items[$i]['pubdate']} ";          
           $s .= " ";
       }
     
      // close channel
      $s .= " ";
      $this->content = $s;
   }
 
   function show() {
       if (emptyempty($this->content)) $this->buildrss();
       header('content-type:text/xml');
       echo($this->content);
   }
 
   function savetofile($fname) {
       if (emptyempty($this->content)) $this->buildrss();
       $handle = fopen($fname, 'wb');
       if ($handle === false)  return false;
       fwrite($handle, $this->content);
       fclose($handle);
   }
}
?>