/**
 * validates email input of user
 */
function checkForm_de() {
	
	var email_regex = /^([_a-zA-Z0-9-]+)(\.[_a-zA-Z0-9-]+)*@([a-zA-Z0-9-]+\.)+([a-zA-Z]{2,4})$/;
	
		if (document.contact.forename.value == "") {
			call_error("Bitte tragen Sie Ihren Vornamen ein!", "forename");
			return false;
		}
		else if (document.contact.surname.value == "") {
				call_error("Bitte tragen Sie Ihren Nachnamen ein!", "surname");
				return false;
			}
			else if (document.contact.email.value == "") {
					call_error("Bitte tragen Sie Ihre E-Mail Adresse ein!", "email");
					return false;
				}
				else if ((email_regex.test(document.contact.email.value)) == false) {
						call_error("Die E-Mail Adresse hat kein gültiges Format!", "email");
						return false;
					}
					else if (document.contact.text.value == "") {
							call_error("Bitte geben Sie einen Text an!", "text");
							return false;
						}
						else {
							clear_error();
							document.contact.submit();
						}
	}
	
	
	function checkForm_eng() {
		
			var email_regex = /^([_a-zA-Z0-9-]+)(\.[_a-zA-Z0-9-]+)*@([a-zA-Z0-9-]+\.)+([a-zA-Z]{2,4})$/;
		
			if (document.contact.forename.value == "") {
				call_error("Please enter your Forename!", "forename");
				return false;
			}
			else 
				if (document.contact.surname.value == "") {
					call_error("Please enter your Surname!", "surname");
					return false;
				}
				else 
					if (document.contact.email.value == "") {
						call_error("Please enter your E-Mail-Address!", "email");
						return false;
					}
					else 
						if ((email_regex.test(document.contact.email.value)) == false) {
							call_error("Please enter a valid E-Mail-Address!", "email");
							return false;
						}
						else 
							if (document.contact.text.value == "") {
								call_error("Please enter your message!", "text");
								return false;
							}
							else {
								clear_error();
								document.contact.submit();
							}	
		
	}


/**
 * clean up messages when user input changes
 */
function clear_error() {
	if (document.getElementById("errormsg").style.display != "none") 
	{
		document.getElementById("errormsg").style.display = "none";
		//document.getElementById(element).style.border = "solid grey 1px";				
	}
}


function call_error(message, element) 
{
	document.getElementById("errormsg").innerHTML = message; 
	document.getElementById("errormsg").style.display = "block";
	//document.getElementById(clear).style.border = "solid black 1px";			
	//document.getElementById(element).style.border = "solid red 1px";
		
}