如何使用客戶端程式設計強制瀏覽器下載圖片？

document.onclick = function (e) {
    e = e || window.event;
    var element = e.target || e.srcElement;
    if (element.innerHTML == "Image") {
        var name = element.nameProp;
        var address = element.href;
        saveImageAs1(element.nameProp, element.href);
        return false; // Prevent default action and stop event propagation
    }
    else
        return true;
};

function saveImageAs1(name, address) {
    if (confirm('you wanna save this image?')) {
        window.win = open(address);
        setTimeout('win.document.execCommand("SaveAs")', 100);
        setTimeout('win.close()', 500);
    }
}