var isloaded = false;
if (document.images) {
    hisimg1off = new Image();hisimg1off.src = "images/history_btn_bioen_off.jpg";
    hisimg2off = new Image();hisimg2off.src = "images/history_btn_worken_off.jpg";
	hisimg3off = new Image();hisimg3off.src = "images/history_btn_freedomen_off.jpg";
	
}
function histimageLoad() {
    if (document.images) {
    hisimg1on = new Image();hisimg1on.src = "images/history_btn_bioen_on.jpg";
    hisimg2on = new Image();hisimg2on.src = "images/history_btn_worken_on.jpg";
    hisimg3on = new Image();hisimg3on.src = "images/history_btn_freedomen_on.jpg";
	
        return (isloaded = true);
    }
}
function hisrollOut(hisimgName) {
    if (document.images) {
        document[hisimgName].src = eval(hisimgName+"off.src");
    }
}
function hisrollIn(hisimgName) {
    if (document.images && (isloaded == true)) {
        document[hisimgName].src = eval(hisimgName+"on.src");
    }
}