function GetBodyNum($mybd,$hnum){  //获取行数
  $contents=explode("<",$mybd);
  $num=count($contents);
  if($num<$spsize) return $newcontents;
  for($z=0;$z<=$hnum;$z++){     
         $newcontents.=$contents[$z]."<";
     }
  $newcontents=rtrim($newcontents,"<");
  return $newcontents;
}