yfdyh000：兴趣所在，见多识广。比不了专业的大神们。回到原帖

/**************************** Firefox Tabs Counter ****************************/
#main-window {
    counter-reset: tabs;
}
.tabbrowser-tab:not(:-moz-any([concealed])) {
    counter-increment: tabs;
}
#alltabs-button {
    visibility: visible !important;
}
#alltabs-button:after {
    content: counter(tabs);
    display: -moz-box;
}
#alltabs-button > :-moz-any(label, image) {
    display: none;
}