问php中strtotime函数的错误

EN

<?php
$date1=$_GET["q1"];
$date2= $_GET["q2"];
// To check date format for From date   
function checkDateFormat1($date1)
{
//match the format of the date
    if( (preg_match(" /^(\d{1,2})\-(\d{1,2})\-(\d{4})$/", $date1,$parts)) || (preg_match(" /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/", $date1,$parts)) )
{
    //check weather the date is valid of not
    //if(checkdate($parts[2],$parts[3],$parts[1]))
    if(checkdate($parts[2],$parts[1],$parts[3]))
    return true;
    else
    return false;
}
else
return false;
}

 // To check the format for To date         
 function checkDateFormat2($date2)
{

if((preg_match(" /^(\d{1,2})\-(\d{1,2})\-(\d{4})$/", $date2,$parts))||(preg_match(" /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/", $date2,$parts)))
{
    //check weather the date is valid of not
    //if(checkdate($parts[2],$parts[3],$parts[1]))
    if(checkdate($parts[2],$parts[1],$parts[3]))
    return true;
    else
    return false;
}
else
return false;
 }                      

if ((checkDateFormat2($date2) && checkDateFormat1($date1))==1)
{
if ($date1==$date2)
{
    $days="1";
    echo $days;
    exit;
}
else
{   
    $difference =(strtotime($date2) - strtotime($date1));
    //calculate the number of days
    $days = round(((($difference/60)/60)/24), 0);
}
 }
 else
 {
     echo "Invalid Date Format"."<br>";
echo "Please make sure that your for date format is MM-DD-YYYY";

exit;
        }

  if ($days<0)
 {
echo "From date cannot be greater than to date";

}   
else
{
$days++;
echo $days;


}   
 ?>