Validating Student Discount

badcode.js

  $(document).ready(function(){ 
    $("button.btn").click(function(){
       
      var NUS_Card_Number = $("#NUS_Card_Number").val();
      var systemIntegratorId = '9000049';//Math.floor((Math.random() * 100000000) + 1);
      
      if(NUS_Card_Number == "")
      {
        alert("NUS Card Number is required."); 
        return false;
      }
      else{          
        
        //alert('hello');
        
       // var get_eight_char = NUS_Card_Number.substr(0, 8);
        
        var check_number = NUS_Card_Number.startsWith("98261360");
        
        if(check_number != false)
        {
          //$('#demo').html('<p>Valid Card Number.</p>');
          window.location.href="/collections/student-discount";
        }
        else{
          $('#demo').html('<p style="color:red;">Invalid Card Number.</p>');
        }
	  });
	});