function validate_index(language){
	if (language == 'en'){
		//test empty username
		if (document.submit_signature.pet_name.value == ""){
			alert(enEmptyUsername)
			document.submit_signature.pet_name.focus();
			return false;
		}
		//test valid username
		if (!is_clean_string(document.submit_signature.pet_name.value)){
			alert(enValidUsername)
			document.submit_signature.pet_name.focus();
			return false;
		}
		//test empty email
		if (document.submit_signature.pet_mail.value == ""){
			alert(enEmptyEmail)
			document.submit_signature.pet_mail.focus();
			return false;
		}
		//test valid email
		if (!testemail(document.submit_signature.pet_mail)){
			alert(enValidEmail)
			document.submit_signature.pet_mail.focus();
			return false;
		}
		//test selected country
		if (document.submit_signature.pet_country.value == ""){
			alert(enEmptyCountry)
			document.submit_signature.pet_country.focus();
			return false;
		}
		/*//test empty city
		if (document.submit_signature.pet_city.value == ""){
			alert(enEmptyCity)
			document.submit_signature.pet_city.focus();
			return false;
		}
		//test valid city name
		if (!is_clean_string(document.submit_signature.pet_city.value)){
			alert(enValidCity)
			document.submit_signature.pet_city.focus();
			return false;
		}*/
		//test empty message
		//if (document.submit_signature.pet_message.value == ""){
		//	alert(enEmptyMessage)
		//	document.submit_signature.pet_message.focus();
		//	return false;
		//}
		return true;
	}
	else {
		//test empty username
		if (document.submit_signature.pet_name.value == ""){
			alert(arEmptyUsername)
			document.submit_signature.pet_name.focus();
			return false;
		}
		//test valid username
		if (!is_clean_string(document.submit_signature.pet_name.value)){
			alert(arValidUsername)
			document.submit_signature.pet_name.focus();
			return false;
		}
		//test empty email
		if (document.submit_signature.pet_mail.value == ""){
			alert(arEmptyEmail)
			document.submit_signature.pet_mail.focus();
			return false;
		}
		//test valid email
		if (!testemail(document.submit_signature.pet_mail)){
			alert(arValidEmail)
			document.submit_signature.pet_mail.focus();
			return false;
		}
		//test selected country
		if (document.submit_signature.pet_country.value == ""){
			alert(arEmptyCountry)
			document.submit_signature.pet_country.focus();
			return false;
		}
		/*//test empty city
		if (document.submit_signature.pet_city.value == ""){
			alert(arEmptyCity)
			document.submit_signature.pet_city.focus();
			return false;
		}
		//test valid city name
		if (!is_clean_string(document.submit_signature.pet_city.value)){
			alert(arValidCity)
			document.submit_signature.pet_city.focus();
			return false;
		}*/
		//test empty message
		//if (document.submit_signature.pet_message.value == ""){
		//	alert(arEmptyMessage)
		//	document.submit_signature.pet_message.focus();
		//	return false;
		//}
		return true;
	}
}

function is_clean_string(str) {
	for(var i = 0; i <str.length; i++) {
		var charat = str.charAt(i);
		if( charat == '`' || charat == '~'  || charat == '!'  || charat == '@'  || charat == '#'  ||
		charat == '$'  || charat == '%'  || charat == '^'  || charat == '&'  || charat == '*'  ||
		charat == '('  || charat == ')'  ||	charat == '`'  || charat == '<'  || charat == '>'  ||
		charat == ';'  || charat == ','  || charat == '|'  || charat == '\\'  || charat == '/'  ||
		charat == '?' || charat == '+' || charat == '='  || charat == '{'  || charat == '}'  ||
		charat == '['  || charat == ']'   || charat == ':'  || charat == "'" ) {
			return false;
		}
	}
	return true;
}

function testemail(obj) {
	var atpos = obj.value.indexOf('@');

	if(atpos == -1) {
		return false;
	}

	if(atpos == 0) {
		return false;
	}

	var dotpos = obj.value.indexOf('.', atpos+2);

	if( dotpos == -1) {
		return false;
	}

	if(dotpos == (obj.value.length - 1) ) {
		return false;
	}

	var fpart = obj.value.substring(0,atpos);
	var host = obj.value.substring(atpos + 1, dotpos);
	var domain = obj.value.substr(dotpos +1);

	if(!( is_clean_string(fpart) && is_clean_string(host) && is_clean_string(domain))) {
		return false;
	}

	var afterat = obj.value.substr(atpos + 1);

	if(afterat.lastIndexOf('.') == (afterat.length - 1)) {
		return false;
	}

	for(var i = 1; i < afterat.length; i++) {
		if(afterat.charAt(i) == '.' && afterat.charAt(i-1) == '.') {
			return false;
		}
	}
	return true;
}