$(function(){

  $(".txtRoom").remove();

  $("#txtAutoFill").on('input',function() {

    var input = parseInt($("#txtAutoFill").val());

    if(typeof(input) == "number"){

    for(var n=1;n<=$("#txtAutoFill").val(); n++) {

      var $i = $("<input />", { 

                  type: "text",

                  id: "txtRoom" + n + "Name",

                  class: "txtRoom"});$("body").append($i);

               }      

    }

    else {

      alert("Please enter a numeric value");

    }

  });

});