I have this Google Sheet cell counter in Apps Script and I don't know how to set the bootstrap progress bar with the "percentage" variable.

GS

function cellCounter() {

  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheets = ss.getSheets();
  var cells = 0;
  sheets.forEach(function(sheet){
    cells = cells   sheet.getMaxRows() * sheet.getMaxColumns();
  });
  var division = cells/10000000*100;
  var percentage =  division.toFixed(0);
  return ( "