$(document).ready(function(){

    $("#questionForm").submit(function() {
		
		if (isRequired("Name", "naam") &
		isRequired("Email", "email") &
		isRequired("Message", "bericht"))
		{
		return true;
		}

      return false;
    });	
	
	function isRequired(fieldName, errorName)
	{
		if ($("#textbox" + fieldName).val() != "") {
        return true;	
      } else {
		$("#error" + fieldName).text("Het veld " + errorName + " is verplicht.").show().fadeOut(1500);
		return false;
	  }
	}
	
	});