Google Sheets - date auto populate when column in specific sheet is edited

Question

Hey I need some help with Google Sheets In sheet 1 "Inventory" I am trying to have the date auto populate in column 8 or I when data is entered in any cell in column 7 or G below row 3

this is what I have tried/as far as I have gotten

    function onEdit(e) {
  if (e.range.columnStart == 7 || e.range.rowStart < 4) return;
  e.source.getActiveSheet().getRange(e.range.rowStart, 9)
        .setValue(Utilities.formatDate(new Date(), "GMT", "dd/MM/yyyy"));
}

Thank you for any help!!

Answer 1

This should fix it:

function onEdit(e) {
      if (e.range.columnStart == 7 || e.range.rowStart < 4){
      e.source.getActiveSheet().getRange(e.range.rowStart, 9)
      .setValue(Utilities.formatDate(new Date(), "GMT", "dd/MM/yyyy"));
      }}

Answer 2

Ended up using this:

 function onEdit() {
 var s = SpreadsheetApp.getActiveSheet();
 if( s.getName() == "Inventory" ) { //checks that we're on the correct sheet
   var r = s.getActiveCell();
   if( r.getColumn() == 7 ) { //checks the column
   var nextCell = r.offset(0, +2);
      if( nextCell.getValue() === '' ) //is empty?
        nextCell.setNumberFormat("MMM dd/YY")
        nextCell.setValue(new Date());
   };
 };
}