// ----------------------------------------------------------------------
// 범위 겹침 검사
// ----------------------------------------------------------------------
function rangeIntersect(R1, R2) {
  if (R1.getLastRow()    < R2.getRow()   ) return false;
  if (R2.getLastRow()    < R1.getRow()   ) return false;
  if (R1.getLastColumn() < R2.getColumn()) return false;
  if (R2.getLastColumn() < R1.getColumn()) return false;
  return true;
}

// ----------------------------------------------------------------------
// 셀이 수정되면 강제로 값 제거
// ----------------------------------------------------------------------
function autoDeleteCellValue(sheet, eventRange, sheetId, targetRangeA1) {
  // if(sheet.getName() !== sheetName) return;
  if(sheet.getSheetId() !== sheetId) return;

  var WHITE = "#ffffff";
  var BLACK = "#000000";

  var targetRange = sheet.getRange(targetRangeA1);
  if(rangeIntersect(targetRange, eventRange)) {

    // 여러 셀을 동시에 수정한 경우, 무시
    // if(eventRange.getNumRows() * eventRange.getNumColumns() > 1)
    //   return;

    eventRange.setValue("");
  }
}

// ----------------------------------------------------------------------
// Event
// ----------------------------------------------------------------------
function onEdit(event) {
  var sheet = SpreadsheetApp.getActiveSheet();
  var eventRange = event.range;
  autoDeleteCellValue(sheet, eventRange, 1623326516, 'V4:V1000');
}