function swapImages(Image1,Image2) { turnOffImage(Image1); turnOnImage(Image2); }
function turnOffImage(ImageName) { var x = document.getElementById(ImageName); x.style.display="none"; }
function turnOnImage(ImageName) { var x = document.getElementById(ImageName); x.style.display="block"; }
function swapDivs(Div1,Div2) { turnOff(Div1); turnOn(Div2); }
function turnOff(DivName) { var x = document.getElementById(DivName); x.style.display="none"; }
function turnOn(DivName) { var x = document.getElementById(DivName); x.style.display="block"; }

function popup(url,name,width,height) {
        var left = Math.floor((screen.width - width) / 2);
        var top = Math.floor((screen.height - height) / 2);
        var popwindow = window.open(url,name,"top=" + top + ",left=" + left + ",height=" + height + ",width=" + width +",status=0,menubar=1,toolbar=0,location=0,directories=0,resizable=1,scrollbars=1");
        if (parseInt(navigator.appVersion) >= 4) { popwindow.window.focus(); }
}