function _render(welTarget, sContentBody) {
        var source = {
            "body": sContentBody,
            "breaks": (welTarget.hasClass('readme-body') ? false : true)
        };

        $.ajax(htVar.sMarkdownRendererUrl,{
            "type": "post",
            "contentType":"application/json; charset=utf-8",
            "data": JSON.stringify(source),
            "success": function(data){
                welTarget.html(data);
                $('pre code').each(function(i, block) {
                    hljs.highlightBlock(block);
                });
            }
        });
    }
If this ajax request is failed, do anything.
Because, the content body not replaced is shown to user before this request.