Google app script monitor spreadsheet selected ranges

Question

I want to write a app script that can get the selected cells

and show it on the html input text.

example:

when I selected A1 cell, then the input text wi

Answer 1

I made this as a possible solution. The app script looks like this. It works quite well. Not sure if it is what you are looking for.

function onOpen() {
  SpreadsheetApp.getUi() // Or DocumentApp or FormApp.
      .createMenu('Custom Menu')
      .addItem('Show sidebar', 'showSidebar')
      .addToUi();
}

function showSidebar() {
  var html = HtmlService.createHtmlOutputFromFile('Page')
      .setTitle('My custom sidebar')
      .setWidth(300);
  SpreadsheetApp.getUi() // Or DocumentApp or FormApp.
      .showSidebar(html);
}

function getActiveRange(){
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getSheetByName('Sheet1');
  var range = sheet.getActiveRange().getA1Notation();
  Logger.log(range)
  return range  
}

The side bar has function that calls every 200th of a second. Making it look like it is getting the data on mouse drag.