Firefox插件：在选项窗口中设置为HomePage NewTab复选框

Question

我想制作firefox插件，将默认的新页面和起始页面更改为特定页面。我尝试使用复选框来启用或禁用设置的“选项”窗口，但它们无法正常工作。请帮帮我。

preferences.xul：

<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>

<prefwindow xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
    <prefpane id="mystartpage-options" label="Opcje">
        <preferences>
            <preference id="extensions.mystartpage.overrideHomePage" name="extensions.mystartpage.overrideHomePage" type="bool"/>
            <preference id="extensions.mystartpage.overrideNewTab" name="extensions.mystartpage.overrideNewTab" type="bool"/>
        </preferences>
        <checkbox id="useAsHomePage" label="Strona startowa" preference="extensions.mystartpage.overrideHomePage"/>
        <checkbox id="openInNewTabs" label="Nowa karta" preference="extensions.mystartpage.overrideNewTab"/>
    </prefpane>
    <script type="application/x-javascript" src="preferences.js"/>
</prefwindow>

preferences.js：

mystartpageoptions = new function () {
    var prefs = Components.classes["@mozilla.org/preferences-service;1"].getService(Components.interfaces.nsIPrefService).getBranch("accessibility.");
    Components.utils.import("resource://gre/modules/Services.jsm");

    if ((Services.prefs.getBoolPref("extensions.mystartpage.overrideNewTab")) = true)
        Services.prefs.setCharPref("browser.newtab.url", "chrome://mystartpage/content/index.html")
    else Services.prefs.clearUserPref("browser.newtab.url");

    if ((Services.prefs.getBoolPref("extensions.mystartpage.overrideHomePage")) = true)
        Services.prefs.setCharPref("browser.startup.homepage", "chrome://mystartpage/content/index.html")
    else Services.prefs.clearUserPref("browser.startup.homepage");
}