if (document.images) {

            img20on = new Image(); img20on.src = "../images/on/profile.gif"; 
            img21on = new Image(); img21on.src = "../images/on/structure.gif";
            img22on = new Image(); img22on.src = "../images/on/mission.gif";  
            img23on = new Image(); img23on.src = "../images/on/act.gif";
            img24on = new Image(); img24on.src = "../images/on/board.gif";
            img25on = new Image(); img25on.src = "../images/on/manage.gif";  
            img26on = new Image(); img26on.src = "../images/on/links.gif";
            img27on = new Image(); img27on.src = "../images/on/career.gif";

            img20off = new Image(); img20off.src = "../images/off/profile.gif"; 
            img21off = new Image(); img21off.src = "../images/off/structure.gif";
            img22off = new Image(); img22off.src = "../images/off/mission.gif";  
            img23off = new Image(); img23off.src = "../images/off/act.gif";
            img24off = new Image(); img24off.src = "../images/off/board.gif";
            img25off = new Image(); img25off.src = "../images/off/manage.gif";  
            img26off = new Image(); img26off.src = "../images/off/links.gif";
            img27off = new Image(); img27off.src = "../images/off/career.gif";

        }

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

function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}