if (document.images) {
var one_on = new Image();
one_on.src = "img/try_now_on.png";
var one_off = new Image();
one_off.src = "img/try_now_off.png";
var two_on = new Image();
two_on.src = "img/see_demo_on.png";
var two_off = new Image();
two_off.src = "img/see_demo_off.png";

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";

}
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");
}