active = 'spurA';
acturl = 'home';

function init() {
changeOpac(100, "spurA");
changeOpac(0,"spurB");
document.getElementById('spurA').style.visibility = 'visible';
document.getElementById('spurB').style.visibility = 'visible';
document.getElementById('spurA').style.zIndex = 2;
document.getElementById('spurB').style.zIndex = 1;
}


function changeSite(newurl) {


if (active == "spurA" && acturl != newurl) {
parent.frames[1].location.href = newurl + ".html";
opacity("spurA", 100, 0, 400);
window.setTimeout("opacity('spurB', 0, 100, 400)", 400);
window.setTimeout("parent.frames[0].location.href = 'leer.html'", 100);
document.getElementById("spurA").style.zIndex = 1;
document.getElementById("spurB").style.zIndex = 2;
active = "spurB";
acturl = newurl;
}

else if (active == "spurB" && acturl != newurl) {
parent.frames[0].location.href = newurl + ".html";
opacity("spurB", 100, 0, 400);
window.setTimeout("opacity('spurA', 0, 100, 400)", 400);
window.setTimeout("parent.frames[1].location.href = 'leer.html'", 100);
document.getElementById("spurB").style.zIndex = 1;
document.getElementById("spurA").style.zIndex = 2;
active = "spurA";
acturl = newurl;
}

}

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

    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++;
        }
    }
}

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(document.getElementById(id).style.opacity == 0) {
        opacity(id, 0, 100, millisec);
    } else {
        opacity(id, 100, 0, millisec);
    }
}