Insert Date Time Formating

I’ve got an old script that gets close, perhaps it helps.

// Inspired by & resources
//   https://www.emeditor.com/forums/topic/option-to-adjust-the-datetime-format-edit-insert-time-and-date/
//   https://www.emeditor.com/forums/topic/insert-long-date/
//   https://www.w3schools.com/jsref/jsref_tolocaledatestring.asp  +  jsref_getmonth.asp  + jsref_getdate.asp

function return_date_long_time() {
  var date = new Date();
  // var n = d.toLocaleDateString();   // old approach - unreliable

  // Date assembly
  var dd   = date.getDate();           // returns the day of the month (from 1 to 31)
  if( dd < 10 )  dd = "0" + dd;

  var MM   = date.getMonth() + 1;      // returns the month (from 0 to 11)!
  if( MM < 10 )  MM = "0" + MM;

  var yyyy = date.getFullYear();       // Returns the year (4 digits)

  // time assembly
  var hh = date.getHours();            // Returns the hour (from 0-23)
  if( hh < 10 )  hh = "0" + hh;
  var mm = date.getMinutes();          // Returns the minutes (from 0-59)
  if( mm < 10 )  mm = "0" + mm;
  var ss = date.getSeconds();          // Returns the seconds (from 0-59)
  if( ss < 10 )  ss = "0" + ss;

  // “Output”
  return( yyyy + "-" + MM + "-" + dd + " " + hh + ":" + mm + ":" + ss );
}

document.write( return_date_long_time() );

You can use the “Date and Time” command instead of the “Time and Date” command, and set the date/time format in the Format page of the Customize dialog box.