GST Number Validation using Javascript or jQuery

This post explains GST number validation using Javascript or jQuery on a text change event.

Introduction

This post explains GST number validation using Javascript or jQuery on a text change event. You need to apply the "gst" class to control and add the below Javascript function.

GST no sample : 05ABDCE1234F1Z2

Code

<script type="text/javascript">
$(document).ready(function () {
$(".gst").change(function () {
                var inputvalues = $(this).val();
                var gstinformat = new RegExp('^[0-9]{2}[A-Z]{5}[0-9]{4}[A-Z]1}[1-9A-Z]{1}Z[0-9A-Z]{1}$');
                if (gstinformat.test(inputvalues)) {
                    return true;
                } else {
                    alert('Please Enter Valid GSTIN Number');
                    $(".gst").val('');
                    $(".gst").focus();
                }
            });
 });
  </script>

ASP Textbox
<asp:TextBox ID="txtGST" MaxLength="15" runat="server" class="gst form-control mandatory" ClientIDMode="Static" placeholder="GST Reg No."></asp:TextBox>

Html input type text
<input type="text" class="gst" >