คำนวณระยะห่างของ 2 วัน ที่รับจาก datepicker 1 และ datepicker 2 (*ไม่นับวันหยุด เสาร์,อาทิตย์ *ไม่นับวันหยุดนักขัตฤกษ์) *คำนวณอันติโนมัติ (ไม่ต้องกดsubmit)

<form method="post"  enctype="multipart/form-data">
  <div class="form-group">
  

   <p>วันที่เริ่มต้น : <input type="text" class="form-control" name="strStartDate" id="strStartDate" required></p>
    <p>วันที่สิ้นสุด : <input type="text" class="form-control" name="strEndDate" id="strEndDate" required></p>
  <input name="btnButton1" type="submit" value="คำนวณจำนวนชั่วโมง" name="cal" >


<?php

if($_POST) {

  function CheckPublicHoliday($strChkDate)
  {
    $objConnect = mysqli_connect("localhost","root","","project") or die("Error Connect to Database");
    $objDB = mysqli_select_db($objConnect,"test");
    $strSQL = "SELECT * FROM public_holiday WHERE publicHoliday = '".$strChkDate."' ";
    $objQuery = mysqli_query($objConnect,$strSQL );
    $objResult = mysqli_fetch_array($objQuery );
    if(!$objResult)
    {
      return false;
    }
    else
    {
      return true;
    }
    mysqli_close($objConnect);
  }
 
  $strStartDate =  isset($_POST['strStartDate']) ? $_POST['strStartDate'] : '';
  $strEndDate = isset($_POST['strEndDate']) ? $_POST['strEndDate'] : '';
  
  $intWorkDay = 0;
  $intHoliday = 0;
  $intPublicHoliday = 0;
  
  $intTotalDay = ((strtotime($strEndDate) - strtotime($strStartDate))/  ( 60 * 60 * 24 )) + 1;
  

  while (strtotime($strStartDate) <= strtotime($strEndDate)) {
    
    $DayOfWeek = date("w", strtotime($strStartDate));
    if($DayOfWeek == 0 or $DayOfWeek ==6)  // 0 = Sunday, 6 = Saturday;
    {
      $intHoliday++;
      //echo "$strStartDate = <font color=red>Holiday</font><br>";
    }
    elseif(CheckPublicHoliday($strStartDate))
    {
      $intPublicHoliday++;
      //echo "$strStartDate = <font color=orange>Public Holiday</font><br>";
    }
    else
    {
      $intWorkDay++;
     // echo "$strStartDate = <b>Work Day</b><br>";
    }
    $DayOfWeek = date("l", strtotime($strStartDate)); // return Sunday, Monday,Tuesday....

    $strStartDate = date ("Y-m-d", strtotime("+1 day", strtotime($strStartDate)));
  }
}
  
 
//$intsumwork = $intWorkDay*7;
 /*echo "<hr>";
  echo "<br>Total Day = $intTotalDay";
  echo "<br>Work Day = $intWorkDay";
  echo "<br>Holiday = $intHoliday";
  echo "<br>Public Holiday = $intPublicHoliday";
  echo "<br>All Holiday = ".($intHoliday+$intPublicHoliday);*/

 // echo "<br>จำนวนชั่วโมง = ".($intWorkDay*7);
 // echo "<br>จำนวนชั่วโมง = $intsumwork";

//value="<?php echo($intsumwork) 

?>
<br/><br>

<div class="form-group">
    <label for="exampleInputEmail1">จำนวนชั่วโมง (*ได้จากการคำนวณ)</label>
    <input text="email"   class="form-control" name="workday" id="workday" aria-describedby="emailHelp"  required>
   </div>
</from>