php给编辑器中的图片添加域名

/** 
 * 替换fckedit中的图片 添加域名 
 * @param  string $content 要替换的内容 
 * @param  string $strUrl 内容中图片要加的域名 
 * @return string  
 * @eg  
 */ 
function replacePicUrl($content = null, $strUrl = null) {  
    if ($strUrl) {  
        //提取图片路径的src的正则表达式 并把结果存入$matches中    
        preg_match_all("/]+>/isU",$content,$matches);  
        $img = "";    
        if(!emptyempty($matches)) {    
        //注意，上面的正则表达式说明src的值是放在数组的第三个中    
        $img = $matches[2];    
        }else {    
           $img = "";    
        }  
          if (!emptyempty($img)) {    
                $patterns= array();    
                $replacements = array();    
                foreach($img as $imgItem){    
                    $final_imgUrl = $strUrl.$imgItem;    
                    $replacements[] = $final_imgUrl;    
                    $img_new = "/".preg_replace("///i","/",$imgItem)."/";    
                    $patterns[] = $img_new;    
                }    
    
                //让数组按照key来排序    
                ksort($patterns);    
                ksort($replacements);    
    
                //替换内容    
                $vote_content = preg_replace($patterns, $replacements, $content);  
          
                return $vote_content;  
        }else {  
            return $content;  
        }                     
    } else {  
        return $content;  
    }  
}