var ie5=(document.getElementById && document.all);
var ns6=(document.getElementById && !document.all);
var lowOpacity = 50;
var highOpacity = 100;
var currentOpacity = 100;
var intValue = 3;
var timeInt = 10;
var changeID;
var prevImg = 0;
var cellText = new Array();
cellText[1] = "GENERAL MEETING";
cellText[2] = "DATING GAME";
cellText[3] = "CAPA FESTIVAL";
cellText[4] = "CAREER FORUM";
cellText[5] = "MILAL EASTER EGG";
cellText[6] = "HIKING TRIP";
cellText[7] = "HAPPY HOUR";
cellText[8] = "ANNA ERIKA VISIT";

function changeOpacity( imgNum, value ) {
  currentOpacity += (value*intValue);
  if (currentOpacity <= highOpacity && currentOpacity >= lowOpacity) {
    if (navigator.userAgent.indexOf('Win') == -1) {
      if (ie5) {
        document.getElementById("img"+imgNum).filters[0].opacity = (value==1) ? highOpacity : lowOpacity;
        document.getElementById("cell"+imgNum).innerHTML = (value == 1) ? '&nbsp;' : cellText[imgNum];
      } else if (ns6) {
        document.getElementById("img"+imgNum).style.MozOpacity = (value==1) ? highOpacity : lowOpacity;
        document.getElementById("cell"+imgNum).innerHTML = (value == 1) ? '&nbsp;' : cellText[imgNum];
      } else {
        return;
      }
    } else {
      if (ie5) {
        document.getElementById("img"+imgNum).filters[0].opacity=currentOpacity;
      } else if (ns6) {
        document.getElementById("img"+imgNum).style.MozOpacity=currentOpacity/100;
      } else {
        return;
      }
    }
    changeID = setTimeout('changeOpacity('+imgNum+', '+value+')', timeInt);
  } else {
    document.getElementById("cell"+imgNum).innerHTML = (value == 1) ? '&nbsp;' : cellText[imgNum];
    currentOpacity = (value==1) ? highOpacity : lowOpacity;
    clearTimeout(changeID);
  }
}


function resetOpacity(imgNum) {
  prevImg = (prevImg == 0) ? imgNum : prevImg;
  currentOpacity = highOpacity;
  if (document.all) {
    document.getElementById("img"+prevImg).filters[0].opacity=highOpacity;
  } else {
    document.getElementById("img"+prevImg).style.MozOpacity=highOpacity/100;
  }
  document.getElementById("cell"+prevImg).innerHTML = "&nbsp;";
  clearTimeout(changeID);
  prevImg = imgNum;
  changeOpacity(imgNum, -1);
}

function clearOpacity(imgNum) {
  clearTimeout(changeID);
  changeOpacity(imgNum, 1);
}

function showImg ( imgName, val ) {
  imgSrc = (val == 1) ? '/image/nav/'+ imgName + '_over.gif' : '/image/nav/'+ imgName + '.gif';
  eval('document.' + imgName + '.src = "' + imgSrc + '"');
}