Survey.StylesManager.applyTheme("modern");
        

//Add a property a text property into all questions types and into page
Survey.Serializer.addProperty("question", "popupdescription:text");
Survey.Serializer.addProperty("page", "popupdescription:text");
function showDescription(element) {
    document.getElementById("questionDescriptionText").innerHTML = element.popupdescription;
    $("#questionDescriptionPopup").modal();
}

            
                var json = { 
    title: "Software developer survey.", 
    pages: [
        { title: "What operating system do you use?", popupdescription:  "Select the operating system you are currently using.",
            questions: [
                {type:"checkbox", name:"opSystem", title: "OS", hasOther: true, isRequired: true, popupdescription:  "If you do not use any of the listed operating system, please select 'others' and type your operating system name.",
                    choices:["Windows", "Linux", "Macintosh OSX"]}
            ]  
        },
        {   title: "What language(s) are you currently using?", popupdescription:  "Select all programming languages you have been using for the last six months.", 
            questions: [
            {type:"checkbox", name:"langs",title:"Please select from the list",popupdescription:  "Select all programming languages you have been using for the last six months.", 
                 colCount: 4, isRequired: true,
                choices:["Javascript", "Java", "Python", "CSS", "PHP", "Ruby", "C++", "C", 
                    "Shell", "C#", "Objective-C", "R", "VimL", "Go", "Perl", "CoffeeScript", 
                    "TeX", "Swift", "Scala", "Emacs Lisp", "Haskell", "Lua", "Clojure", 
                    "Matlab", "Arduino", "Makefile", "Groovy", "Puppet", "Rust", "PowerShell"]
            }
        ]},        
        { title: "Please enter your name and e-mail", popupdescription:  "We will not share this information with any third-party organization.", 
            questions: [ 
            {type: "text", name: "name", title: "Name:", popupdescription:  "Please, type your name as 'Given Name' 'Family Name'."}, 
            {type: "text", name: "email", title: "Your e-mail", popupdescription:  "Please, make sure you do not misspell your e-mail."}]
        }]
};

                window.survey = new Survey.Model(json);
            
        
            survey.onComplete.add(function(result) {
            document.querySelector('#surveyResult').textContent =
            "Result JSON:\n" + JSON.stringify(result.data, null, 3);
            });
        
survey.onAfterRenderQuestion.add(function(survey, options){
    //Return if there is no description to show in popup
    if(!options.question.popupdescription) return;
    //Add a button;
    var btn = document.createElement("button");
    btn.type = "button";
    btn.className = "btn btn-info btn-xs";
    
        btn.style.position = "absolute";
        btn.style.marginLeft = "20px"
    
    btn.innerHTML = "More Info";
    var question = options.question;
    btn.onclick = function() { showDescription(question); }
    var header = options.htmlElement.querySelector("h5");
    var span = document.createElement("span");
    span.innerHTML = "  ";
    header.appendChild(span);
    header.appendChild(btn);
});

survey.onAfterRenderPage.add(function(survey, options){
    //Return if there is no description to show in popup
    if(!options.page.popupdescription) return;
    //Add a button;
    var btn = document.createElement("button");
    btn.type = "button";
    btn.className = "btn btn-info btn-xs";
    
    btn.style.position = "absolute";
    btn.style.marginLeft = "20px"
    
    btn.innerHTML = "More Info";
    btn.onclick = function() { showDescription(survey.currentPage); }
    var header = options.htmlElement.querySelector("h4");
    var span = document.createElement("span");
    span.innerHTML = "  ";
    header.appendChild(span);
    header.appendChild(btn);
});        
            var app = new Vue({
            el: '#surveyElement',
            data:
            {
            survey: survey
            }
            });
        

                    

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Use events to customize survey rendering, Vue Survey Library Example</title>

<meta name="viewport" content="width=device-width" />
    <script src="https://unpkg.com/jquery"></script>
    <script src="https://unpkg.com/vue/dist/vue.js"></script>
<script src="https://surveyjs.azureedge.net/1.7.17/survey.vue.js"></script>
<link href="https://surveyjs.azureedge.net/1.7.17/modern.css" type="text/css" rel="stylesheet" />
    <link rel="stylesheet" href="./index.css">
<link rel="stylesheet" href="https://unpkg.com/bootstrap@3.3.7/dist/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
    
<!-- Modal -->
<div id="questionDescriptionPopup" class="modal fade" role="dialog">
    <div class="modal-dialog">

        <!-- Modal content-->
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal">&times;</button>
                <h4 class="modal-title">Modal Header</h4>
            </div>
            <div class="modal-body">
                <p><div id="questionDescriptionText"></div></p>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
            </div>
        </div>

    </div>
</div>            <div id="surveyElement" style="display:inline-block;width:100%;">
                <survey :survey='survey' />
            </div>
    <div id="surveyResult"></div>

<script type="text/javascript" src="./index.js"></script>

</body>
</html>