/**
 * 日期格式化成xx天前
 *
 * @param 
 * @arrange (512.笔记) jb51.cc
 **/
function ago($d) {
 $c = getdate();
 $p = array('year','mon','mday','hours','minutes','seconds');
 $display = array('year','month','day','hour','minute','second');
 $factor = array(0,12,30,24,60,60);
 $d = datetoarr($d);
 for ($w = 0; $w < 6; $w++) {
  if ($w > 0) {
   $c[$p[$w]] += $c[$p[$w-1]] * $factor[$w];
   $d[$p[$w]] += $d[$p[$w-1]] * $factor[$w];
  }
  if ($c[$p[$w]] - $d[$p[$w]] > 1) { 
   return ($c[$p[$w]] - $d[$p[$w]]).' '.$display[$w].'s ago';
  }
 }
 return '';
}
 
// you can replace this if need be. This converts my dates returned from a MysqL date string into 
//   an array object similar to that returned by getdate().
function datetoarr($d) {
 preg_match("/([0-9]{4})(\\-)([0-9]{2})(\\-)([0-9]{2}) ([0-9]{2})(\\:)([0-9]{2})(\\:)([0-9]{2})/",$d,$matches);
    return array( 
  'seconds' => $matches[10],'minutes' => $matches[8],'hours' => $matches[6],'mday' => $matches[5],'mon' => $matches[3],'year' => $matches[1],);
}
/***   代码来自编程之家 jb51.cc（jb51.cc）   ***/