function rollover(filename,obj){
 obj.src = filename;
}
$(document).ready(function(){
    $(".img_fader").hover(function() {
      $(this).stop().animate({opacity: "1"}, 'slow');
    },
    function() {
      $(this).stop().animate({opacity: "0.4"}, 'slow');
    });
  });
<!-- added for contact form start -->
<!-- default values -->
var ctformval = {
dectname:'(Ihr Name *)', plctname:'(Nazwisko *)', enctname:'(Your name *)', jpctname:'(お名前 *)',
dectemail :'(Ihre E-mail *)', plctemail :'(E-mail *)', enctemail :'(Your E-mail *)', jpctemail :'(E-mail *)',
dectformsub:'(Fachgebiet)', plctformsub:'(tematyka)', enctformsub:'(Text subject)', jpctformsub:'(題名)',
dectdeadline:'(Deadline)', plctdeadline:'(Termin oddania)', enctdeadline:'(Deadline)', jpctdeadline:'(希望締切日)',
dectcomment:'(Ihre Nachricht an uns...)', plctcomment:'(wiadomość...)', enctcomment:'(your message to us...)', jpctcomment:'(コメントをご記入ください。)',
dectquiz:'Aufgabe', plctquiz:'Quiz', enctquiz:'Quiz', jpctquiz:'Quiz',
dectmsg:'Bitte die Pflichtfelder ausfüllen!', plctmsg:'Wypelnij pola obowiazkowe!', enctmsg:'Please check your input!', jpctmsg:'入力内容をご確認ください。'
};
var num01;
var num02;
<!-- set default values -->
function setDefaultVal(){
 var lan = document.getElementById("page_language").value;
 if (document.getElementById("realname").value != ctformval[lan+"ctname"]) {
  document.getElementById("realname").value = ctformval[lan+"ctname"];
 }
 if (document.getElementById("email").value != ctformval[lan+"ctemail"]) {
  document.getElementById("email").value = ctformval[lan+"ctemail"];
 }
 if (document.getElementById("form_subject").value != ctformval[lan+"ctformsub"]) {
  document.getElementById("form_subject").value = ctformval[lan+"ctformsub"];
 }
 if (document.getElementById("datepicker").value != ctformval[lan+"ctdeadline"]) {
  document.getElementById("datepicker").value = ctformval[lan+"ctdeadline"];
 }
 if (document.getElementById("message").value != ctformval[lan+"ctcomment"]) {
  document.getElementById("message").value = ctformval[lan+"ctcomment"];
 }
}
<!-- clear default values -->
function clickclear(thisfield, ctobjname){
var lan = document.getElementById("page_language").value;
if (thisfield.value ==  ctformval[lan+ctobjname] ) {
  thisfield.value = "";
  }
}
<!-- set default values -->
function clickrecall(thisfield, ctobjname) {
 var lan = document.getElementById("page_language").value;
 if (thisfield.value == "") {
  thisfield.value = ctformval[lan+ctobjname];
 }
}
<!-- create security question -->
function secQuestion() {
 var lan = document.getElementById("page_language").value;
 var now = new Date();
 var sec = now.getSeconds();
 var min = now.getMinutes();
 num01 = sec % 10;
 num01 +=1;
 num02 = (min + sec) % 10;
 num02 +=1;
 document.write(ctformval[lan+"ctquiz"] + ": " + num01 + " + " + num02 + " = " + "<input type='text' id='quizanswer' name='quizanswer' class='ctfield' size='5' maxlength='3' value='' />");
}
<!-- check values before submit -->
function chkSubmit() {
 var lan = document.getElementById("page_language").value;
 var corAnswer = num01 + num02;
 var formAnswer = document.getElementById("quizanswer").value;
 if (document.getElementById("realname").value == '' || document.getElementById("realname").value == ctformval[lan+"ctname"]) {
  alert(ctformval[lan+"ctmsg"]);
  document.getElementById("realname").focus();
  return false;
 }
 if (document.getElementById("email").value == '' || document.getElementById("email").value == ctformval[lan+"ctemail"]) {
  alert(ctformval[lan+"ctmsg"]);
  document.getElementById("email").focus();
  return false;
 }
 if (corAnswer != formAnswer) {
  alert(ctformval[lan+"ctmsg"]);
  document.getElementById("quizanswer").value = "";
  document.getElementById("quizanswer").focus();
  return false;
 }
}
<!-- datepicker -->
jQuery(function() {
 var defaultlan = '';
 var ctimagepath = 'css/images/calendar.jpg';
 if (document.getElementById("page_language")) {
 defaultlan = document.getElementById("page_language").value;
 }
 if (defaultlan != "de") {
  ctimagepath = '../' + ctimagepath;
 }
 jQuery("#datepicker").datepicker({
  minDate: -0, maxDate: '+1Y',
  showButtonPanel: true,
  showOn: 'button',
  buttonImage: ctimagepath,
  buttonImageOnly: true
 });
 $.datepicker.regional['de'] = {
  closeText: 'schließen',
  prevText: '&#x3c;zurück',
  nextText: 'Vor&#x3e;',
  currentText: 'heute',
  monthNames: ['Januar','Februar','März','April','Mai','Juni',
  'Juli','August','September','Oktober','November','Dezember'],
  monthNamesShort: ['Jan','Feb','Mär','Apr','Mai','Jun',
  'Jul','Aug','Sep','Okt','Nov','Dez'],
  dayNames: ['Sonntag','Montag','Dienstag','Mittwoch','Donnerstag','Freitag','Samstag'],
  dayNamesShort: ['So','Mo','Di','Mi','Do','Fr','Sa'],
  dayNamesMin: ['So','Mo','Di','Mi','Do','Fr','Sa'],
  weekHeader: 'Wo',
  dateFormat: 'dd.mm.yy',
  firstDay: 1,
  isRTL: false,
  showMonthAfterYear: false,
  yearSuffix: ''
 };
 $.datepicker.regional['pl'] = {
  closeText: 'Zamknij',
  prevText: '&#x3c;Poprzedni',
  nextText: 'Następny&#x3e;',
  currentText: 'Dziś',
  monthNames: ['Styczeń','Luty','Marzec','Kwiecień','Maj','Czerwiec',
  'Lipiec','Sierpień','Wrzesień','Październik','Listopad','Grudzień'],
  monthNamesShort: ['Sty','Lu','Mar','Kw','Maj','Cze',
  'Lip','Sie','Wrz','Pa','Lis','Gru'],
  dayNames: ['Niedziela','Poniedziałek','Wtorek','Środa','Czwartek','Piątek','Sobota'],
  dayNamesShort: ['Nie','Pn','Wt','Śr','Czw','Pt','So'],
  dayNamesMin: ['N','Pn','Wt','Śr','Cz','Pt','So'],
  weekHeader: 'Tydz',
  dateFormat: 'dd.mm.yy',
  firstDay: 1,
  isRTL: false,
  showMonthAfterYear: false,
  yearSuffix: ''
 };
 $.datepicker.regional['jp'] = {
  buttonImage: '../css/images/calendar.jpg',
  closeText: '閉じる',
  prevText: '&#x3c;前',
  nextText: '次&#x3e;',
  currentText: '今日',
  monthNames: ['1月','2月','3月','4月','5月','6月','7月','8月','9月','10月','11月','12月'],
  monthNamesShort: ['1月','2月','3月','4月','5月','6月','7月','8月','9月','10月','11月','12月'],
  dayNames: ['日曜日','月曜日','火曜日','水曜日','木曜日','金曜日','土曜日'],
  dayNamesShort: ['日','月','火','水','木','金','土'],
  dayNamesMin: ['日','月','火','水','木','金','土'],
  weekHeader: '週',
  dateFormat: 'yy/mm/dd',
  firstDay: 0,
  isRTL: false,
  showMonthAfterYear: true,
  yearSuffix: '年'
  };
 $.datepicker.setDefaults($.datepicker.regional[defaultlan]);
});
<!-- added for contact form End -->