[html] How can I show dots ("...") in a span with hidden overflow?

Try this,

.truncate {
    display:inline-block;
    width:180px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

add .truncate class to your element.

EDIT,

Above solution is not working in all the browsers. you can try following jQuery plugin with cross browser support.

(function ($) {
    $.fn.ellipsis = function () {
        return this.eachAsync({
            delay: 100,
            bulk: 0,
            loop: function (index) {
                var el = $(this);

                if (el.data("fullText") !== undefined) {
                    el.html(el.data("fullText"));
                } else {
                    el.data("fullText", el.html());
                }

                if (el.css("overflow") == "hidden") {
                    var text = el.html();
                    var t = $(this.cloneNode(true))
                                        .hide()
                                        .css('position', 'absolute')
                                        .css('overflow', 'visible')
                                        .width('auto')
                                        .height(el.height())
                                        ;

                    el.after(t);

                    function width() { return t.width() > el.width(); };

                    var func = width;
                    while (text.length > 0 && width()) {
                        text = text.substr(0, text.length - text.length * 25 / 100);
                        t.html(text + "...");
                    }

                    el.html(t.html());
                    t.remove();
                }
            }
        });
    };
})(jQuery);

how to call,

$("#content_right_head span").ellipsis();