if (document.images) {
    questionsOn = new Image();
    questionsOn.src = "http://www2.library.ucla.edu/images/b_questions_1.gif";
    questionsOff = new Image();
    questionsOff.src = "http://www2.library.ucla.edu/images/b_questions_0.gif";

    questionsWhtOn = new Image();
    questionsWhtOn.src = "http://www2.library.ucla.edu/images/w_questions_1.gif";
    questionsWhtOff = new Image();
    questionsWhtOff.src = "http://www2.library.ucla.edu/images/w_questions_0.gif";
}
function turnOn(imageName) {
    if (document.images) {
        document[imageName].src = eval(imageName + "On.src");
    }
}
function turnOff(imageName) {
    if (document.images) {
        document[imageName].src = eval(imageName + "Off.src");
    }
}