Identify card type from card number

I am trying to identify card number to display the credit card processing company icon on the side of the field. So far I can identify the card number now but I can't display the icon on the side. It only returns the company name which does not work. Can you help me out?

Added into templates/payment/form-creditcard.php

<script type="text/javascript">

  function GetCardType(number)
  {
      // visa
      var re = new RegExp("^4");
      if (number.match(re) != null)
          return "Visa";

      // Mastercard 
      // Updated for Mastercard 2017 BINs expansion
       if (/^(5[1-5][0-9]{14}|2(22[1-9][0-9]{12}|2[3-9][0-9]{13}|[3-6][0-9]{14}|7[0-1][0-9]{13}|720[0-9]{12}))$/.test(number)) 
          return "Mastercard";

      // AMEX
      re = new RegExp("^3[47]");
      if (number.match(re) != null)
          return "AMEX";

      // Discover
      re = new RegExp("^(6011|622(12[6-9]|1[3-9][0-9]|[2-8][0-9]{2}|9[0-1][0-9]|92[0-5]|64[4-9])|65)");
      if (number.match(re) != null)
          return "Discover";

      // Diners
      re = new RegExp("^36");
      if (number.match(re) != null)
          return "Diners";

      // Diners - Carte Blanche
      re = new RegExp("^30[0-5]");
      if (number.match(re) != null)
          return "Diners - Carte Blanche";

      // JCB
      re = new RegExp("^35(2[89]|[3-8][0-9])");
      if (number.match(re) != null)
          return "JCB";

      // Visa Electron
      re = new RegExp("^(4026|417500|4508|4844|491(3|7))");
      if (number.match(re) != null)
          return "Visa Electron";

      return "";
  }

  document.getElementById('omise_card_number').oninput = function() {
    this.value = GetCardType(this.value)
  }
</script>

omise / omise-woocommerce

Identify card type from card number #267