title: How to avoid IE11 "slow" evaluation of CSS :invalid and :valid pseudo selectors
body: <p>I'm aware of this question that shows :valid and :invalid pseudo selectors not working at all in IE11:</p>
  
  <p><a href="https://stackoverflow.com/questions/34556276/css-formvalid-selector-doesnt-work-in-ie11">CSS form:valid selector doesn&#39;t work in IE11</a></p>
  
  <p>Yet there is also this example of floating labels:</p>
  
  <p><a href="https://snook.ca/archives/html_and_css/floated-label-pattern-css" rel="nofollow noreferrer">https://snook.ca/archives/html_and_css/floated-label-pattern-css</a></p>
  
  <p>Here, IE11 is behaving differently. At first, it does not seem to work. You type in the fields of the form and the CSS that is supposed to apply, doesn't, which is different from Chrome and Firefox. </p>
  
  <p>However, when you exit the field, or move to the next field, you do see the CSS applied, even in IE11. As if it is "one behind". </p>
  
  <p>I'm facing this exact same issue in my own implementation, which is not public. Is there a solution (non-JS) to work around this strange evaluation behavior of IE11?</p>