I have been trying to track Events occurring in my website using JavaScript. But that code is not working

Question

jQuery(document).ready(function() {
  console.log("function reached");
  jQuery("form").submit(function() {
    analytics.track("Apply Now", {
      firstName: document.getElementById("header_form_first_name").value,
      `Help to track firstname by using ID`
    });
  });
});

Above code is my code in WordPress but it returns null value and I have no idea about why it is returning null value

Answer 1

$(function(){
  // Use FORM ID to identify the form and invoke the submit
  $('#myForm').submit(function()
  {
   analytics.track("Apply Now", {
   firstName: 
   document.getElementById("header_form_first_name").value,
  `Help to track firstname by using ID`
  });
 }