$(".inputbutton").on("click", function(e){
  
  var emailExp = /^[\w\-\.\+]+\@[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/;
  var errorMessage  = $(".errorMessage");
  var hasError = false;
  var $email = $('#ctl12_ctl04_FLBT4');
  
  $(".inputtext").each(function(){
    var $this = $(this);
    
    if(($this.val() == "") || !emailExp.test($email.val())){
      hasError = true;
      $this.addClass("inputError");
      errorMessage.html("<p>Error: Please correct errors above</p>");
      e.preventDefault();
    }if($this.val() != ""){
      $this.removeClass("inputError"); 
    }else{
      return true; 
    }
  }); //Input
  
  errorMessage.slideDown(700);
});