title: What exactly is touching the DOM?
body: <p>I am currently trying to implement Angular Universal in my app, but I have a lot of manipulations in my app. 
  I do not completely understand what touching the DOM actually is.</p>
  
  <p>Is changing the text inside a div using jquery touching the DOM?</p>
  
  <p>Having a button scroll to the bottom?</p>
  
  <pre><code>$('html, body').animate({
    scrollTop: $("#sectAbout").offset().top
  }, 1000);
  </code></pre>
  
  <p>Adding a class?:</p>
  
  <pre><code>$('#smallLogo').addClass(this.diffAni[picked]);
  </code></pre>
  
  <p>having an image rotate?</p>
  
  <p>Listening for scroll events?:</p>
  
  <pre><code>$(document).scroll(function() { 
  scroll_start = $(this).scrollTop();
  </code></pre>
  
  <p>etc.
  Can you give some examples of what touching the DOM actually means and/or some clear signs of touching the DOM?
  Also is there any way to test an app without allowing it to touch the DOM?</p>
  
  <p>Some alternatives would be helpful. I know adding a class is really simple with just using ngClass, but how about the scroll events?</p>