app service dopost function form submit redirect to the website

I am sending html form data to google sheets. While it has been done, I'm unable to redirect it to the website. Currently, once the form has been submitted, it redirects to scripts page where it shows a success message. I want to it to redirect back to the website page. Please suggest how it can be done.

here is the code. This code was readily available online; contributed by OmPrakash95 and jamiewilson

App service

const sheetName = 'Sheet1'
const scriptProp = PropertiesService.getScriptProperties()

function initialSetup () {
  const activeSpreadsheet = SpreadsheetApp.getActiveSpreadsheet()
  scriptProp.setProperty('key', activeSpreadsheet.getId())
}

function doPost (e) {
  const lock = LockService.getScriptLock()
  lock.tryLock(10000)

  try {
    const doc = SpreadsheetApp.openById(scriptProp.getProperty('key'))
    const sheet = doc.getSheetByName(sheetName)

    const headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0]
    const nextRow = sheet.getLastRow() + 1

    const newRow = headers.map(function(header) {
      return header === 'Date' ? new Date() : e.parameter[header]
    })

    sheet.getRange(nextRow, 1, 1, newRow.length).setValues([newRow])

    return ContentService
      .createTextOutput(JSON.stringify( 'Thanks for submitting! Someone from our team will reach out to you! Visit '))
      .setMimeType(ContentService.MimeType.JSON)
  }

  catch (e) {
    return ContentService
      .createTextOutput(JSON.stringify({ 'result': 'error', 'error': e }))
      .setMimeType(ContentService.MimeType.JSON)
  }

  finally {
    lock.releaseLock()
  }
}

html

  <form id="form" action="https://script.google.com/macros/s/AKfycbyJJc1i3740zFxXMgxBQPowxwND5Cxb-n4a2ZnYphvLfrBqNfnqlFOcmHpfwMNh_jk/exec" method="POST">
  <label for="fname">First name:</label><br>
  <input type="text" id="fname" name="fname" placeholder="John"><br>
  <label for="lname">Last name:</label><br>
  <input type="text" id="lname" name="lname" placeholder="Doe"><br>
  <button type="submit">Send</button>