<script type="text/javascript">
 $(window).load(function(){
  $('#tb1').on("change keyup",function(e){
  if(this.value!==undefined || this.value!==null || $.trim(this.value)!=="" ) {
    $("#area2").show();
   }
  });
 $('#tb1').focus('change', function() {
  $("#area2").show();
  });
 }); // Closes window.load
</script>
You can use like this