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Calculate difference between two dates (in hours)

I searched EE and found similar posts but none of the solutions are 100% right. I Need a script that will take two dates (xx/xx/xxxx) and time (xx:xx am/pm) and return the difference in time between the two in total hours. Output formatted as x.x hours. Below is code that is pretty close with a couple exceptions:

1. AM/PM doesn't appear to work
2. I need to remove the submit button and have it automatically update the difference field

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>Time Delta</title>
 
<script type='text/javascript'>
  <!-- Original:  Ronnie T. Moore                             -->
  <!-- Web Site:  The JavaScript Source                       -->
 
  <!-- This script and many more are available free online at -->
  <!-- The JavaScript Source!! http://javascript.internet.com -->
 
  <!-- Begin
  function isValidDate( dateStr ) {
    // Date validation function courtesty of
    // Sandeep V. Tamhankar (stamhankar@hotmail.com) -->
 
    // Checks for the following valid date formats:
    // MM/DD/YY   MM/DD/YYYY   MM-DD-YY   MM-DD-YYYY
 
    var datePat = /^(\d{1,2})(\/|-)(\d{1,2})\2(\d{4})$/; // requires 4 digit year
 
    var matchArray = dateStr.match( datePat ); // is the format ok?
    if ( matchArray == null ) {
      alert( dateStr + " Date is not in a valid format." )
      return false;
    }
    month = matchArray[ 1 ]; // parse date into variables
    day   = matchArray[ 3 ];
    year  = matchArray[ 4 ];
    if ( month < 1 || month > 12 ) { // check month range
      alert( "Month must be between 1 and 12." );
      return false;
    }
    if ( day < 1 || day > 31 ) {
      alert("Day must be between 1 and 31.");
      return false;
    }
    if ( ( month == 4 || month == 6 || month == 9 || month == 11 ) && day == 31 ) {
      alert("Month "+month+" doesn't have 31 days!")
      return false;
    }
    if (month == 2) { // check for february 29th
      var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
      if (day>29 || (day==29 && !isleap)) {
        alert("February " + year + " doesn't have " + day + " days!");
        return false;
      }
    }
    return true;
  }
 
  function isValidTime( timeStr ) {
    // Time validation function courtesty of
    // Sandeep V. Tamhankar (stamhankar@hotmail.com) -->
 
    // Checks if time is in HH:MM:SS AM/PM format.
    // The seconds and AM/PM are optional.
 
    function d2( val ) {
      return ( val < 10 ) ? '0' + val : val;
    }
 
    var timePat = /^(\d{1,2}):(\d{2})(:(\d{2}))?(\s?(AM|am|PM|pm))?$/;
 
    var matchArray = timeStr.match( timePat );
    if ( matchArray == null ) {
      alert( "Time is not in a valid format." );
      return false;
    }
    hour   = matchArray[ 1 ];
    minute = matchArray[ 2 ];
    if ( matchArray[ 4 ] ) {
      second = matchArray[ 4 ]
    } else {
      second = 0
    }
 
    if ( matchArray[ 5 ] ) {
      ampm = matchArray[ 5 ];
    } else {
      ampm = null
    }
//  alert( 'time: "' + hour + '" "' + minute + '" "' + second + '" "' + ampm + '"' )
 
    if ( hour < 0  || hour > 23 ) {
      alert( "Hour must be between 1 and 12. (or 0 and 23 for military time)" );
      return false;
    }
 
    if ( hour <= 12 && ( ampm == null ) ) {
      if ( confirm( "Please indicate which time format you are using.  OK = Standard Time, CANCEL = Military Time" ) ) {
        alert( "You must specify AM or PM." );
        return false;
      }
    }
 
    if  ( hour > 12 && ( ampm != null ) ) {
      alert( "You can't specify AM or PM for military time." );
      return false;
    }
 
    if ( minute < 0 || minute > 59 ) {
      alert( "Minute must be between 0 and 59." );
      return false;
    }
    timeVal = d2( hour ) + ':' + d2( minute )
//  alert( 'timeVal: ' + timeVal )
 
    if ( second && ( second < 0 || second > 59 ) ) {
      alert( "Second must be between 0 and 59." );
      return false;
    } else
      timeVal += ':' + d2( second )
//  alert( 'timeVal: ' + timeVal )
 
    if ( ampm && ( hour < 13 ) ) {
      timeVal += ' AM'
    } else if ( ampm ) {
      timeVal += ' PM'
    }
//  alert( 'timeVal: ' + timeVal )
 
    return true;
  }
 
  function dateDiff( dateform ) {
    date1 = new Date();
    date2 = new Date();
    diff  = new Date();
 
    if ( isValidDate( dateform.firstdate.value ) && isValidTime( dateform.firsttime.value ) ) { // Validates first date
//    date1temp = new Date( dateform.firstdate.value + " " + dateform.firsttime.value );
      date1temp = new Date( dateform.firstdate.value + " " + timeVal );
      date1.setTime( date1temp.getTime() );
    } else
      return false; // otherwise exits
 
    if ( isValidDate( dateform.seconddate.value ) && isValidTime( dateform.secondtime.value ) ) { // Validates second date
//    date2temp = new Date( dateform.seconddate.value + " " + dateform.secondtime.value );
      date2temp = new Date( dateform.seconddate.value + " " + timeVal );
      date2.setTime( date2temp.getTime() );
    } else
      return false; // otherwise exits
 
    // sets difference date to difference of first date and second date
 
    diff.setTime( Math.abs( date1.getTime() - date2.getTime() ) );
//  alert( 'date1: ' + date1 + '\ndate2: ' + date2 + '\ndiff: ' + diff )
 
    timediff = diff.getTime();
 
//  weeks = Math.floor( timediff / ( 1000 * 60 * 60 * 24 * 7 ) );
//  timediff -= weeks * ( 1000 * 60 * 60 * 24 * 7 );
//
//  days = Math.floor( timediff / ( 1000 * 60 * 60 * 24 ) );
//  timediff -= days * ( 1000 * 60 * 60 * 24 );
 
    hours = Math.floor( timediff / ( 1000 * 60 * 60 ) );
//  timediff -= hours * ( 1000 * 60 * 60 );
 
//  mins = Math.floor( timediff / ( 1000 * 60 ) );
//  timediff -= mins * ( 1000 * 60 );
//
//  secs = Math.floor( timediff / 1000 );
//  timediff -= secs * 1000;
 
//  dateform.difference.value = weeks + " weeks, " + days + " days, " + hours + " hours, " + mins + " minutes, and " + secs + " seconds";
//  alert( hours )
    dateform.difference.value =  hours.toFixed( 2 )
 
    return false; // form should never submit, returns false
  }
//  End -->
</script>
 
</head>
<body>
 
<center>
<form onSubmit="return dateDiff(this);">
<table>
<tr><td>
<pre>
First Date:   Date: <input type=text name=firstdate value="" size=10 maxlength=10>  (MM/DD/YYYY format)
              Time: <input type=text name=firsttime value="" size=10 maxlength=10>  (HH:MM:SS format)
 
Second Date:  Date: <input type=text name=seconddate value="" size=10 maxlength=10>  (MM/DD/YYYY format)
              Time: <input type=text name=secondtime value="" size=10 maxlength=10>  (HH:MM:SS format)
 
<center><input type=submit value="Calculate Difference!">
 
Date Difference:<br>
<input type=text name=difference value="" size=60>
</center>
</pre>
</td></tr>
</table>
</form>
</center>
 
</body>
</html>

Open in new window

David H.H.Lee

Hi ianmeu1,
I've amended the code as given based on the questions:

1. AM/PM doesn't appear to work
- refer code, change array index for second

2. I need to remove the submit button and have it automatically update the difference field
- You can put some timer to auto calculate the different.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>Time Delta</title>
 
<script type='text/javascript'>
  <!-- Original:  Ronnie T. Moore                             -->
  <!-- Web Site:  The JavaScript Source                       -->
 
  <!-- This script and many more are available free online at -->
  <!-- The JavaScript Source!! http://javascript.internet.com -->
 
  <!-- Begin
  function isValidDate( dateStr ) {
    // Date validation function courtesty of
    // Sandeep V. Tamhankar (stamhankar@hotmail.com) -->
 
    // Checks for the following valid date formats:
    // MM/DD/YY   MM/DD/YYYY   MM-DD-YY   MM-DD-YYYY
 
    var datePat = /^(\d{1,2})(\/|-)(\d{1,2})\2(\d{4})$/; // requires 4 digit year
 
    var matchArray = dateStr.match( datePat ); // is the format ok?
    if ( matchArray == null ) {
      alert( dateStr + " Date is not in a valid format." )
      return false;
    }
    month = matchArray[ 1 ]; // parse date into variables
    day   = matchArray[ 3 ];
    year  = matchArray[ 4 ];
    if ( month < 1 || month > 12 ) { // check month range
      alert( "Month must be between 1 and 12." );
      return false;
    }
    if ( day < 1 || day > 31 ) {
      alert("Day must be between 1 and 31.");
      return false;
    }
    if ( ( month == 4 || month == 6 || month == 9 || month == 11 ) && day == 31 ) {
      alert("Month "+month+" doesn't have 31 days!")
      return false;
    }
    if (month == 2) { // check for february 29th
      var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
      if (day>29 || (day==29 && !isleap)) {
        alert("February " + year + " doesn't have " + day + " days!");
        return false;
      }
    }
    return true;
  }
 
  function isValidTime( timeStr ) {
    // Time validation function courtesty of
    // Sandeep V. Tamhankar (stamhankar@hotmail.com) -->
 
    // Checks if time is in HH:MM:SS AM/PM format.
    // The seconds and AM/PM are optional.
 
    function d2( val ) {
      return ( val < 10 ) ? '0' + val : val;
    }
 
    var timePat = /^(\d{1,2}):(\d{2})(:(\d{2}))?(\s?(AM|am|PM|pm))?$/;
 
    var matchArray = timeStr.match( timePat );
    if ( matchArray == null ) {
      alert( "Time is not in a valid format." );
      return false;
    }
    hour   = matchArray[ 1 ];
    minute = matchArray[ 2 ];
    
if ( matchArray[ 3 ] ) {
      second = matchArray[ 3 ]
    } else {
      second = 0
    }
 
    if ( matchArray[ 4 ] ) {
      ampm = matchArray[ 4 ];
    } else {
      ampm = null
    }
 
//  alert( 'time: "' + hour + '" "' + minute + '" "' + second + '" "' + ampm + '"' )
 
    if ( hour < 0  || hour > 23 ) {
      alert( "Hour must be between 1 and 12. (or 0 and 23 for military time)" );
      return false;
    }
 
    if ( hour <= 12 && ( ampm == null ) ) {
      if ( confirm( "Please indicate which time format you are using.  OK = Standard Time, CANCEL = Military Time" ) ) {
        alert( "You must specify AM or PM." );
        return false;
      }
    }
 
    if  ( hour > 12 && ( ampm != null ) ) {
      alert( "You can't specify AM or PM for military time." );
      return false;
    }
 
    if ( minute < 0 || minute > 59 ) {
      alert( "Minute must be between 0 and 59." );
      return false;
    }
 
    timeVal = d2( hour ) + ':' + d2( minute )
 
//  alert( 'timeVal: ' + timeVal )
 
    if ( second && ( second < 0 || second > 59 ) ) {
      alert( "Second must be between 0 and 59." );
      return false;
    } else
      timeVal += ':' + d2( second )
//  alert( 'timeVal: ' + timeVal )
 
    if ( ampm && ( hour < 13 ) ) {
      timeVal += ' AM'
    } else if ( ampm ) {
      timeVal += ' PM'
    }
//  alert( 'timeVal: ' + timeVal )
 
    return true;
  }
 
  function dateDiff() {
    date1 = new Date();
    date2 = new Date();
    diff  = new Date();
 
    if(document.getElementById('firstdate').value==''||document.getElementById('firsttime').value==''||document.getElementById('firsttime').value==''||document.getElementById('secondtime').value==''){
      return false;     
}
 
    if ( isValidDate( document.getElementById('firstdate').value ) && isValidTime( document.getElementById('firsttime').value ) ) { // Validates first date
     date1temp = new Date(  document.getElementById('firstdate').value + " " + timeVal );
      date1.setTime( date1temp.getTime() );
    } else
      return false; // otherwise exits
 
    if ( isValidDate( document.getElementById('seconddate').value ) && isValidTime( document.getElementById('secondtime').value ) ) { // Validates second date
      date2temp = new Date( document.getElementById('seconddate').value + " " + timeVal );
      date2.setTime( date2temp.getTime() );
    } else
      return false; // otherwise exits
 
    // sets difference date to difference of first date and second date
 
    diff.setTime( Math.abs( date1.getTime() - date2.getTime() ) );
 
    timediff = diff.getTime();
 
    hours = Math.floor( timediff / ( 1000 * 60 * 60 ) );
//  timediff -= hours * ( 1000 * 60 * 60 );
 
  mins = Math.floor( timediff / ( 1000 * 60 ) );
//  timediff -= mins * ( 1000 * 60 );
//
   secs = Math.floor( timediff / 1000 );
//  timediff -= secs * 1000;
 
//   document.getElementById('difference').value = weeks + " weeks, " + days + " days, " + hours + " hours, " + mins + " minutes, and " + secs + " seconds";
   
     //alert('Hours ' + hours);
     //alert('mins ' + mins);
     //alert('secs ' + secs);
 
     document.getElementById('difference').value =  hours.toFixed( 2 ) 
     
    return false; // form should never submit, returns false
  }
//  End -->
</script>
 
</head>
<body onload="setInterval('dateDiff()',3000);">
 
<center>
<form>
<table>
<tr><td>
<pre>
First Date:   Date: <input type=text name=firstdate value="" size=10 maxlength=10>  (MM/DD/YYYY format)
              Time: <input type=text name=firsttime value="" size=11 maxlength=11>  (HH:MM:SS AM/PM format)
 
Second Date:  Date: <input type=text name=seconddate value="" size=10 maxlength=10>  (MM/DD/YYYY format)
              Time: <input type=text name=secondtime value="" size=11 maxlength=11>  (HH:MM:SS AM/PM format)
 
<center><input type=submit value="Calculate Difference!">
 
Date Difference:<br>
<input type=text name=difference value="" size=60>
</center>
</pre>
</td></tr>
</table>
</form>
</center>
 
</body>
</html>

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ASKER CERTIFIED SOLUTION

David H.H.Lee

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ianmeu1

ASKER

Nice! That works great in IE but I just noticed it's not working in FireFox? Do you think this is related to the timer to auto calculate the difference?

ianmeu1

ASKER

I also noticed the minutes calculation doesn't work.

-Thanks for your help