function showimg(img)
{
    document.getElementById(img).style.opacity == 100;
    document.getElementById(img).style.filter = "alpha(opacity=100)";
    document.getElementById(img).style.visibility = "visible";

}


function hideimg(img)
{
    document.getElementById(img).style.opacity == 0;
    document.getElementById(img).style.filter = "alpha(opacity=0)";
    document.getElementById(img).style.visibility = "hidden";

}



function blend(img)
{
    document.getElementById(img).style.opacity = 0;
    document.getElementById(img).style.filter = "alpha(opacity=0)";
    document.getElementById(img).style.visibility = "visible";
  setTimeout(function(){startblend(img)},5000);
}


function startblend(img) {
  shiftOpacity(img, 200);
  setTimeout(function(){startblend(img)},5000);
}

function mblend(s,e) {
    hideall(s,e)
    setTimeout(function(){startmblend(s,e)},5000);
}


var c=0;
function startmblend(s,e) {
    if(c == -1) {
      img = "img"+(e) ;
      shiftOpacity(img, 200);
      hideall(s,e-1);
    }
    else {
      img = "img"+(c+s) ;
      document.getElementById(img).style.visibility = "visible";
      shiftOpacity(img, 200);
    }

    if((c+s) < e) {
      c=c+1;
    }

    else{
      c = -1;
    }

    t = setTimeout(function(){startmblend(s,e)},5000);
}


function hideall(s,e){
  for(s;s <= e;s++){
    img = "img" + s;
    document.getElementById(img).style.opacity = 0;
    document.getElementById(img).style.filter = "alpha(opacity=0)";
  }

}

function opacity(id, opacStart, opacEnd, millisec) {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;

    //determine the direction for the blending, if start and end are the same nothing happens
    if(opacStart > opacEnd) {
        for(i = opacStart; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    } else if(opacStart < opacEnd) {
        for(i = opacStart; i <= opacEnd; i++)
            {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    }
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
    var object = document.getElementById(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
}

function shiftOpacity(id, millisec) {
    //if an element is invisible, make it visible, else make it invisible
    if(document.getElementById(id).style.opacity == 0) {
        opacity(id, 0, 100, millisec);
    } else {
        opacity(id, 100, 0, millisec);
    }
}