Site Content Type in SharePoint 2013 using JSOM

'use strict';

var context = SP.ClientContext.get_current(); //App Web Context
var hostWebUrl, hostWebContext;

// This code runs when the DOM is ready and creates a context object which is needed to use the SharePoint object model
$(document).ready(function () {
    //Get the URI decoded URLs.
    hostWebUrl = decodeURIComponent(getQueryStringParameter("SPHostUrl"));
    hostWebContext = new SP.AppContextSite(context, hostWebUrl);
});

// Retrieve a query string value.
function getQueryStringParameter(paramToRetrieve) {
    var params = document.URL.split("?")[1].split("&");
    for (var i = 0; i < params.length; i = i + 1) {
        var singleParam = params[i].split("=");
        if (singleParam[0] == paramToRetrieve) return singleParam[1];
    }
}

//Create Content Type
function createContentType() {
    if (hostWebContext != undefined && hostWebContext != null) {
        var hostWeb = hostWebContext.get_web();
        var contentTypeCollection = hostWeb.get_contentTypes();
        //Get Document Content type by its Id. We will use Document Content Type as Base Content Type
        //to create a new Content Type.
        //Refer article for Ids of other Content Types.
        var contentType = contentTypeCollection.getById("0x0101");
        //Creating new Content Type
        var newContentType = new SP.ContentTypeCreationInformation();
        newContentType.set_name('Employee');
        newContentType.set_group('Employee Details');
        newContentType.set_description('Content Type for Employee Details.');
        //Set Base Content Type
        newContentType.set_parentContentType(contentType);
        contentTypeCollection.add(newContentType);
        context.load(contentTypeCollection);
        context.executeQueryAsync(
            function () {
                alert('Content type created successfully on Host Web.');
            },
           function onContenttypeFailed(sender, args) {
               alert('Content type creation failed. Error: ' + args.get_message() + '\n' + args.get_stackTrace());
           });
    }
}