(new Image()).src = "image/summarize-3.jpg";
(new Image()).src = "image/function-3.jpg";
(new Image()).src = "image/profit-3.jpg";
(new Image()).src = "image/summarize-2.jpg";
(new Image()).src = "image/function-2.jpg";
(new Image()).src = "image/profit-2.jpg";
function change(e, i) {
    unActiveAll(e.parentNode);
    var panel1 = document.getElementById("panel1");
    var panel2 = document.getElementById("panel2");
    var panel3 = document.getElementById("panel3");

    switch (i) {
        case 1:
            panel1.style.display = "block";
            panel2.style.display = "none";
            panel3.style.display = "none";
            e.src = "image/summarize-3.jpg";
            break;
        case 2:
            panel2.style.display = "block";
            panel1.style.display = "none";
            panel3.style.display = "none";
            e.src = "image/function-3.jpg";

            break;
        case 3:
            panel2.style.display = "none";
            panel1.style.display = "none";
            panel3.style.display = "block";
            e.src = "image/profit-3.jpg";
            break;
        default:
            break;
    }

}
function unActiveAll(e) {
    var imgs = e.getElementsByTagName("img");
    //  alert(imgs.length);
    for (var i = 0; i < imgs.length; i++) {
        imgs[i].src = imgs[i].src.replace("3.jpg", "2.jpg");
    }
}