JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://unpkg.com/underscore"></script>
<script src="https://unpkg.com/backbone"></script>
<script src="https://unpkg.com/vue"></script>
<div id="app"/>

JavaScript

var LinkView = Backbone.View.extend({
	template: "<a href='#'>Link</a>",
	render: function() {
		this.$el.html(this.template);
    return this;
	}
});

var HeaderView = Vue.extend({
	template: "<div id='header'><h3>Hello World!</h3></div>",
  mounted: function() {
    var linkView = new LinkView().render();
  	$(this.$el).append(linkView.$el);
  }
});

var AppView = Backbone.View.extend({
	template: "<div id='header'></div><div id='body'></div>",
	render: function() {
		this.$el.html(this.template);
    
    var headerView = new HeaderView({
    	el: this.$('#header')[0]
    });
    
    return this;
	}
});

var instance = new AppView({
	el: '#app'
}).render();