if (document.images) {

var nav1 = new Image();
nav1.src = "/exhibitions/exoplanets/images/nav/interferometer_but_off.gif";
var nav1on = new Image();
nav1on.src = "/exhibitions/exoplanets/images/nav/interferometer_but_on.gif";

var nav2 = new Image();
nav2.src = "/exhibitions/exoplanets/images/nav/coronagraph_but_off.gif";
var nav2on = new Image();
nav2on.src = "/exhibitions/exoplanets/images/nav/coronagraph_but_on.gif";

var nav3 = new Image();
nav3.src = "/exhibitions/exoplanets/images/nav/meet_but_off.gif";
var nav3on = new Image();
nav3on.src = "/exhibitions/exoplanets/images/nav/meet_but_on.gif";

var nav4 = new Image();
nav4.src = "/exhibitions/exoplanets/images/nav/behindthescenes_but_off.gif";
var nav4on = new Image();
nav4on.src = "/exhibitions/exoplanets/images/nav/behindthescenes_but_on.gif";

var nav5 = new Image();
nav5.src = "/exhibitions/exoplanets/images/nav/resources_but_off.gif";
var nav5on = new Image();
nav5on.src = "/exhibitions/exoplanets/images/nav/resources_but_on.gif";

var nav6 = new Image();
nav6.src = "/exhibitions/exoplanets/images/nav/educatorsguide_but_off.gif";
var nav6on = new Image();
nav6on.src = "/exhibitions/exoplanets/images/nav/educatorsguide_but_on.gif";



var tick1 = new Image();
tick1.src = "/content/images/but_buytickets_off.gif";
var tick1on = new Image();
tick1on.src = "/content/images/but_buytickets_on.gif";
}


function imgon(name)  {
if (document.images){
document[name].src = eval(name + "on.src");}
}

function imgoff(name)  {
if (document.images){
document[name].src = eval(name + ".src");}
}