Knockout markdown and ellipsis (less,more) handler , depended to https://code.google.com/p/pagedown/

example.html

  <p data-bind="markdown: content></p>
  
  or
  
  <p data-bind="markdown: {text:content,options: { maxLength:500 }}></p>

knockout.markdown.js

var _markdownHandler = function (element, valueAccessor, allBindings, viewModel, bindingContext) {
        var options = {
            maxLength: 100,
            moreText: "more",
            lessText: "less",
            moreClass: "markdown-more-text",
            lessClass: "markdown-less-text",

        };
        var binding = ko.unwrap(valueAccessor());

        var text = "";
        if (binding === null) {
            binding = "";
        }

        if (typeof binding === "string") {
            text = binding;
        } else {
            text = ko.unwrap(binding.text);
            if (binding.options) {
                options = ko.unwrap(binding.options);
            }
        }

        var converter = new Markdown.getSanitizingConverter();
        var truncate = options.maxLength && options.maxLength != 0 && text.length > options.maxLength;
        var el = $(element);

        var fullText = converter.makeHtml(text);
        if (truncate) {
            converter.hooks.chain("preConversion", function(text) {
                var truncatedValue = text.length > options.maxLength ? text.substring(0, Math.min(text.length, options.maxLength)) + " ..." : text;
                return truncatedValue;
            });

            var truncatedText = converter.makeHtml(text);
            el.html("").append($("<div class='js-markdown-text'>").append(truncatedText));
            el.append(String.format("<a class='js-markdown-toggle' {0}' data-action='more' href='#' >{1}</a>", options.moreClass, options.moreText));

            ko.utils.registerEventHandler(el.find('.js-markdown-toggle'), "click", function(ev) {
                ev.stopPropagation();
                ev.preventDefault();
                var t = $(this);
                if (t.data("action") == 'more') {
                    t.removeClass(options.moreClass);
                    t.addClass(options.lessClass);
                    t.text(options.lessText);
                    t.data("action", "less");

                    el.find(".js-markdown-text").html(fullText);
                } else {
                    t.removeClass(options.lessClass);
                    t.addClass(options.moreClass);
                    t.text(options.moreText);
                    t.data("action", "more");

                    el.find(".js-markdown-text").html(truncatedText);
                }
            });
        } else {
            el.html(fullText);
        }

    };

    ko.bindingHandlers.markdown = {
        update: _markdownHandler,
        init: _markdownHandler
    };

hallo