Question

How would I achieve the pseudo-code below in JavaScript? I want to include the date check in the second code excerpt, where txtDate is for the BilledDate.

If ABS(billeddate – getdate)  >  31 then yesno “The date you have entered is more than a month from today, Are you sure the date is correct,”.   if (txtDate && txtDate.value == '') {     txtDate.focus();     alert('Please enter a date in the 'Date' field.')     return false; } 

Answer 1

Generally speaking you work with Date-objects in javascript, and these should be constructed with the following syntax:

    var myDate = new Date(yearno, monthno-1, dayno);     //you could put hour, minute, second and milliseconds in this too 

Beware, the month-part is an index, so january is 0, february is 1 and december is 11 !-)

Then you can pull out anything you want, the .getTime() thing returns number of milliseconds since start of Unix-age, 1/1 1970 00:00, så this value you could subtract and then look if that value is greater than what you want:

//today (right now !-) can be constructed by an empty constructor var today = new Date(); var olddate = new Date(2008,9,2); var diff = today.getTime() - olddate.getTime(); var diffInDays = diff/(1000*60*60*24);//24 hours of 60 minutes of 60 second of 1000 milliseconds  alert(diffInDays); 

This will return a decimal number, so probably you’ll want to look at the integer-value:

alert(Math.floor(diffInDays));