Set Default Values in SharePoint List Edit View using JavaScript

Question

I want to set the values of 3 SharePoint list columns when it goes into edit mode using JavaScript in SharePoint Online.

I have a list in a popup form that looks like the below. When the user clicks the Edit button to go into edit mode, I want the EntryDateTime to be set to the current date/time, initials to be set to the initials of the current user, and Project to be set to the current project. How/where can I fire the JavaScript?

Answer 1

Here is the solution:

<script  src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<script>
  $(document).on("click", "#Hero-WPQ2 a.ms- heroCommandLink:contains('edit')", function(evt) { 
    var t = setInterval(function() {
    if($("#spgridcontainer_WPQ2_leftpane_mainTable").length) {
        clearInterval(t);
        var d = formatDate(new Date());
        $("#spgridcontainer_WPQ2_leftpane_mainTable tr:last td:eq(1)").text(d);

        var name = ""; // can't be done with this method as the name don't appear on the page, only something like : Jim's Mega project
        $("#spgridcontainer_WPQ2_leftpane_mainTable tr:last td:eq(2)").text(name);

        var currentproject = "";
        var arr = $("h1:contains('Project Communications: Project ')").text().match(/Project\sCommunications:\sProject\s(\d*)\s/);
        if(arr && arr[1])
            currentproject = arr[1];
        $("#spgridcontainer_WPQ2_leftpane_mainTable tr:last td:eq(6)").text(currentproject)
    }
},100);
});

function formatDate(dateVal) {
  var newDate = new Date(dateVal);
  var sMonth = padValue(newDate.getMonth() + 1);
  var sDay = padValue(newDate.getDate());
  var sYear = newDate.getFullYear();
  var sHour = newDate.getHours();
  var sMinute = padValue(newDate.getMinutes());
  var sAMPM = "AM";
  var iHourCheck = parseInt(sHour);

  if (iHourCheck > 12) {
    sAMPM = "PM";
    sHour = iHourCheck - 12;
  }
  else if (iHourCheck === 0) {
    sHour = "12";
  }

  sHour = padValue(sHour);

  return sMonth + "/" + sDay + "/" + sYear + " " + sHour + ":" + sMinute + " " + sAMPM;
}

function padValue(value) {
  return (value < 10) ? "0" + value : value;
}
</script>

Credit to leakim971