//比较两个时间的函数，值为正/负/0
function   get2DT1SubDT2Operate($DateTime1,   $DateTime2= " ",   $RetFormat= "S ")
 {
 //如果$DateTime2为空，设置为当前的时间
 if   ($DateTime2   ==   " ")   $DateTime2   =   date( "Y-m-d  //格式化时间
 $DateTimeTemp   =   strftime( "%Y-%m-%d",strtotime($DateTime1));//格式化字符串
 //$DateTimeTemp   =   strftime( "%Y-%m-%d   %H:%M:%S ",strtotime($DateTime1));//格式化字符串
 $iTemp[ "Y "]   =   intval(substr($DateTimeTemp,0,4));
 $iTemp[ "M "]   =   intval(substr($DateTimeTemp,5,2));
 $iTemp[ "D "]   =   intval(substr($DateTimeTemp,8,2));
 $iTemp[ "H "]   =   intval(substr($DateTimeTemp,11,2));
 $iTemp[ "I "]   =   intval(substr($DateTimeTemp,14,2));
 $iTemp[ "S "]   =   intval(substr($DateTimeTemp,17,2));
 $aDT[]   =   $iTemp;
 unset($iTemp);
 $DateTimeTemp   =   strftime( "%Y-%m-%d ",strtotime($DateTime2));//格式化字符串

 //$DateTimeTemp   =   strftime( "%Y-%m-%d   %H:%M:%S ",strtotime($DateTime2));//格式化字符串
 $iTemp[ "Y "]   =   intval(substr($DateTimeTemp,0,4));
 $iTemp[ "M "]   =   intval(substr($DateTimeTemp,5,2));
 $iTemp[ "D "]   =   intval(substr($DateTimeTemp,8,2));
 $iTemp[ "H "]   =   intval(substr($DateTimeTemp,11,2));
 $iTemp[ "I "]   =   intval(substr($DateTimeTemp,14,2));
 $iTemp[ "S "]   =   intval(substr($DateTimeTemp,17,2));
 $aDT[]   =   $iTemp;
 //$DateTime2   -   $DateTime1的时间差值，单位秒
 $iSec   =   mktime($aDT[1][ "H "],   $aDT[1][ "I "],   $aDT[1][ "S "],
       $aDT[1][ "M "],   $aDT[1][ "D "],   $aDT[1][ "Y "])   -
 mktime($aDT[0][ "H "],   $aDT[0][ "I "],   $aDT[0][ "S "],
       $aDT[0][ "M "],   $aDT[0][ "D "],  //格式化输出值
 if   ($RetFormat   ==   "S ")
 return   $iSec;
 elseif   ($RetFormat   ==   "I ")
 return   $iSec   /   60;
 elseif   ($RetFormat   ==   "H ")
 return   $iSec   /   (60   *   60);
 elseif   ($RetFormat   ==   "D ")
 return   $iSec   /   (60   *   60   *   24);
 }//输出值
  echo get2DT1SubDT2Operate( "2012-10-22", "".date('c')."", "D ")
  ?>

//检查时间A是否符合format的函数
function chkDateFormat($format, $strTime) {
 $tem = date ( $format, strtotime ( $strTime ) );
 if ($strTime == $tem)
 return true;
 else
 return false;
 }if (! chkDateFormat ( 'Y-m-d H:i', '2009/08/19 12:00' ))

 echo "时间格式有误！";

 //将某时间与当前时间比较的函数
 function isBeforeToday($strTime) {

 if (strtotime ( $strTime ) < time ())
 return true;
 else
 return false;
 }if (isBeforeToday ( '2008/08/19 12:00' ))

 echo "该时间已过期";

 //比较两个时间的函数
 function aLessThanB($strTime1, $strTime2) {

 if (strtotime ( $strTime1 ) < strtotime ( $strTime2 ))
 return true;
 else
 return false;
 }if(aLessThanB('2008/08/19','2009/08/19'))
 echo "A 时间早于B时间";