function doLogin(){
    var username = $("#username").val();
    var password = $("#password").val();
    if(username == ""){
      alert("Please enter a username.");
    }
    else if(password == ""){
      alert("Please enter your password.");
    }
    else{
      //submit form
      $.post("/doLoginAjax.php", { username: username, password: password },
        function(data){
           if(data == "Success"){
             window.location = "user/dashboard.php";
           }
           else{
             window.location = "login.php";
           }
      });
      
    }

  }