if (document.images) {
var three_on = new Image();
three_on.src = "img/try_ptsd_on.png";
var three_off = new Image();
three_off.src = "img/try_ptsd_off.png";
var four_on = new Image();
four_on.src = "img/demo_ptsd_on.png";
var four_off = new Image();
four_off.src = "img/demo_ptsd_off.png";

var five_on = new Image();
five_on.src = "img/button_demolist_on.png";
var five_off = new Image();
five_off.src = "img/button_demolist_off.png";
var six_on = new Image();
six_on.src = "img/button_yes_on.png";
var six_off = new Image();
six_off.src = "img/button_yes_off.png";

var seven_on = new Image();
seven_on.src = "img/privacy_button_on.png";
var seven_off = new Image();
seven_off.src = "img/privacy_button_off.png";
var eight_on = new Image();
eight_on.src = "img/security_button_on.png";
var eight_off = new Image();
eight_off.src = "img/security_button_off.png";
var nine_on = new Image();
nine_on.src = "img/tracking_button_on.png";
var nine_off = new Image();
nine_off.src = "img/tracking_button_off.png";
var ten_on = new Image();
ten_on.src = "img/diff_button_on.png";
var ten_off = new Image();
ten_off.src = "img/diff_button_off.png";
}
function swapOn(imgName) {
if (document.images)
document[imgName].src = eval(imgName + "_on.src");
}
function swapOff(imgName) {
if (document.images)
document[imgName].src = eval(imgName + "_off.src");
}