title: Find out if element has a declared value
body: <p>I'd like to add a method to a module (think web-component) that detects whether a height has been set to its root element and if not - calculates its height based on other factors.</p>
  
  <p>This module has some absolute positioning and other 'fancy' stuff so normal flow is out of the question.</p>
  
  <p>I was thinking of looping through <code>document.styleSheets</code> and checking for the id or class of the root element in the <code>selectorText</code> of each <code>cssRule</code> then parsing the <code>cssText</code> or looking for a non-empty key of 'height' inside the <code>style</code> object.</p>
  
  <p>Is there a better (or standard) way of doing this?</p>
  
  <p>PS - I might have just solved it while formulating the question, so if you run into the same issue - here ya go!</p>