How to calculation time elapsed since this web page was last modified.

[Gretsch]

Web, html, javascript,

Hi,
I need to calculate the time since this .htm file was last modified. {which I can then use in a calculation, rather than display, so days&decimals format would be OK}
I can get the time NOW, but I am having trouble understanding the format/content of the document.lastModified field.
Any help would be much appreciated - thanks

I have a function to calculate the difference between the 2 dates, but when i run it I get: Object doesn't support this property or method

<script language="JavaScript" type="text/javascript">
<!--
function days_between(date1, date2) {                //calculates day & fractions of days between 2 dates_times
 
    var ONE_DAY = 1000 * 60 * 60 * 24                // Nb The number of milliseconds in one day
    // Convert both dates to milliseconds
    var date1_ms = date1.getTime()
    var date2_ms = date2.getTime()
 
    // Calculate the difference in milliseconds
    var difference_ms = Math.abs(date1_ms - date2_ms)
 
    // Convert back to days&decimals and return
//    return Math.round(difference_ms/ONE_DAY)     // forget about rounding
      return (difference_ms/ONE_DAY)
}
 
//-->
</script>
 

And to get the 2 dates I am using:

<script type="text/javascript">       
  <!--
  var current_date = new Date()
 
  document.writeln("Current time: " + current_date + "<p />")    // print for testing
 
  lastmod = document.lastModified     // get string of last modified date
  lastmoddate = Date.parse(lastmod)   // convert modified string to date
  if(lastmoddate == 0){               // unknown date (or January 1, 1970 GMT)
     document.writeln("Last Modified: Unknown")
     } else {
     document.writeln("Last Modified: " + lastmod + "<p />")
 
// Call the days_between function
  var time_elapsed = days_between(current_date, lastmod )
// and for testing just print it for now..
  document.writeln("Time  elapsed =: " + time_elapsed + "<p />")
}
//-->
</script>
 

[mrhoo]

Date.parse returns an integer- the time stamp. Use it to create a Date object:


var lastmod = new Date(Date.parse(document.lastModified))

Then subtract lastmod from new Date(), and use that integer (milliseconds difference) to calculate the difference in days, hours etc.

[Gretsch]

Brilliant,
It now works.
Thanks very much for your help - and so quick !!

Date.parse returns an integer- the time stamp. Use it to create a Date object:


var lastmod = new Date(Date.parse(document.lastModified))

Then subtract lastmod from new Date(), and use that integer (milliseconds difference) to calculate the difference in days, hours etc.

[pbmods]

Heya, Gretsch. Welcome to TSDN!

Please use CODE tags when posting source code:

[CODE=javascript]
JavaScript code goes here.
[/CODE]

Glad to hear you got it working! Good luck with your project, and if you ever need anything, post back anytime :)