function isValidEmail(email, required) {
			if (required==undefined) {   // if not specified, assume it's required
				required=true;
			}
			if (email==null) {
				if (required) {
					return false;
				}
				return true;
			}
			if (email.length==0) {  
				if (required) {
					return false;
				}
				return true;
			}
			if (! allValidChars(email)) {  // check to make sure all characters are valid
				return false;
			}
			if (email.indexOf("@") < 1) { //  must contain @, and it must not be the first character
				return false;
			} else if (email.lastIndexOf(".") <= email.indexOf("@")) {  // last dot must be after the @
				return false;
			} else if (email.indexOf("@") == email.length) {  // @ must not be the last character
				return false;
			} else if (email.indexOf("..") >=0) { // two periods in a row is not valid
			return false;
			} else if (email.indexOf(".") == email.length) {  // . must not be the last character
			return false;
			}
			return true;
		}
		
		function allValidChars(email) {
		  var parsed = true;
		  var validchars = "abcdefghijklmnopqrstuvwxyz0123456789@.-_";
		  for (var i=0; i < email.length; i++) {
			var letter = email.charAt(i).toLowerCase();
			if (validchars.indexOf(letter) != -1)
			  continue;
			parsed = false;
			break;
		  }
		  return parsed;
		}

			   	  
		function changeTraining(ser, id, training_id, lang, user_id, field)
		{
			$.post("/ajax/ajax_changetraining.php", {
									ser: ser,
									id: id,
									training_id : training_id, 
									lang: lang,
									user_id: user_id, 
									field: field
								},
								function (data) {
								   var obj = $.evalJSON(data); 
								   $("#duration"+ser+"").val(obj.duration);
								}
			);
		}
		
		function initialtraining(id, lang)
		{
			$.get("/ajax/ajax_training.php", {
					id: id,
					lang: lang
				},
				function (data) {
				 
				 if (id>0) {
					 $("#firstline").after(data);
					 
					 //$("#traininglist"+id+"").find("#calc_date_from"+id+"").mask('99/99/9999');
					 //$("#traininglist"+id+"").find("#calc_date_to"+id+"").mask('99/99/9999');			 
					 $("#traininglist"+id+"").find("#duration"+id+"").attr("disabled", true); 
				   
					 $("#traininglist"+id+"").find("#addtraining"+id+"").show();
					 $("#traininglist"+id+"").find("#removetraining"+id+"").hide();
				 }
				}
			 );
		}
		
		function addtraining(id, lang)
		{
			$.get("/ajax/ajax_training.php", {
					id: id,
					lang: lang
				},
				function (data) { 
				 var obj=$("#traininglist"+id+"");
				 if ( (id>0) && (obj.size()==0) )
				 {
				     var previd=id-1;
					 $("#traininglist"+previd+"").after(data);
					 
					 //$("#traininglist"+id+"").find("#calc_date_from"+id+"").mask('99/99/9999');
					 //$("#traininglist"+id+"").find("#calc_date_to"+id+"").mask('99/99/9999');
				   	 $("#traininglist"+id+"").find("#duration"+id+"").attr("disabled", true);
				   	 
					 $("#traininglist"+previd+"").find("#addtraining"+previd+"").hide();
					 if (previd>1) {
					 	$("#traininglist"+previd+"").find("#removetraining"+previd+"").show();
					 }
				  }
				}
			 );
		}
		
		function removetraining(id)
		{
			if (id>1) {
				 $("#traininglist"+id+"").fadeOut(10,function () {
						 var ct = $("#traininglist"+id+"").find("#error"+id+"").children().size();  
						 totalerrors=totalerrors-ct;
				
						 $("#traininglist"+id+"").remove();
						 $("#clear"+id+"").remove();
						 $("#line"+id+"").remove();
		
						 var previd=id-1;
						 $("#traininglist"+previd+"").find("#addtraining"+previd+"").show();
				  });


		    }
		}