<!--

var darkened_pics = new Array();
var lighted_pics = new Array();


function preloadButtonSet(num,dark,light) {
 darkened_pics[num] = new Image();
 darkened_pics[num].src = dark;
 lighted_pics[num] = new Image();
 lighted_pics[num].src = light;
}

preloadButtonSet(0,"misc_images/lifetree_off.jpg","misc_images/lifetree_on.jpg");
preloadButtonSet(1,"misc_images/earthscience_off.jpg","misc_images/earthscience_on.jpg");
preloadButtonSet(2,"misc_images/terrapin_off.jpg","misc_images/terrapin_on.jpg");
preloadButtonSet(3,"misc_images/home_off.gif","misc_images/home_on.gif");


function lighten(num) {
 if (document.images)
  eval("document.button"+num+".src = lighted_pics["+num+"].src;");
 return false;
}
function darken(num) {
 if (document.images)
  eval("document.button"+num+".src = darkened_pics["+num+"].src;");
 return false;
}



//->