google script if range change code example

Example 1: setValue()

SpreadsheetApp.getActive().getRange("A1").setValue('abc');

Example 2: google apps script to get spreadsheet range to a variable

var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheets()[0];
var range = sheet.getRange('A1:D10');
//range.activate();
var values = range.getValues();
//Logger.log(values[0][0]);
var selection = sheet.getSelection();
// Current cell: A1
var currentCell = selection.getCurrentCell();
// Active Range: A1:D10
var activeRange = selection.getActiveRange();