Change dependent drop down column in Google Script Editor - validation

Question

How can I change this script to apply drop downs in Column B & C instead of A & B? (The script seems to work perfectly if the drop downs are in Column A & B.)
Column A will be for dates, column B will be drop down list (from "Crops" sheet) and column C will be a dependent drop down list (from "Crops" sheet). When I change the "First Level Column" (line 3) and "Second Level Column" (line 4) to equal 2 (col B) & 3 (col C) respectively in the script editor and then input a date in column A in the worksheet, the drop down options in Column B & C disappear completely.
var MainWsName = "Harvest";
var CropsWsName = "Crops";
var firstLevelColumn = 2;
var secondLevelColumn = 3;
var ws = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(MainWsName);
var wsCrops = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(CropsWsName);
var Crops = wsCrops.getRange(2, 1,wsCrops.getLastRow()-1,3).getValues();
function onEdit(activeCell){
var activeCell = ws.getActiveCell();
var val = activeCell.getValue();
var r = activeCell.getRow();
var c = activeCell.getColumn();
var wsName = activeCell.getSheet().getName();
if (wsName == MainWsName && c === firstLevelColumn && r > 1){
applyFirstLevelValidation(val,r)
}//close If
}// end onEdit
function applyFirstLevelValidation(val,r){
if(val === ""){
ws.getRange(r, secondLevelColumn).clearContent();
ws.getRange(r, secondLevelColumn).clearDataValidations();
} else {
ws.getRange(r, secondLevelColumn).clearContent();
var filteredCrops = Crops.filter(function(o){ return o[0] === val });
var listToApply = filteredCrops.map(function(o){ return o[1] });
var cell = ws.getRange(r, secondLevelColumn);
applyValidationToCell(listToApply,cell);
}
}
function applyValidationToCell(list,cell){
var rule = SpreadsheetApp
.newDataValidation()
.requireValueInList(list)
.setAllowInvalid(false)
.build();
cell.setDataValidation(rule);
}

Answer 1

function onEdit(e) {
if (sh.getName() == 'Harvest' && e.range.columnStart > 1 && e.range.columnStart < 4 && e.range.rowStart > 1) {
applyFirstLevelValidation(e.value, e.range.rowStart)
}
}
You can't use parameters with trigger functions. I don't see how the onEdit(e)