Pre-hiding snippet for Adobe Target with asynchronous tags deployment

AdobeTargetPreHiding.js

<script>
   //prehiding snippet for Adobe Target with asynchronous tags deployment
   ;(function(win, doc, style, timeout) {
   var STYLE_ID = 'at-body-style';
   function getParent() {
      return doc.getElementsByTagName('head')[0];
   }
   function addStyle(parent, id, def) {
      if (!parent) {
      return;
      }
      var style = doc.createElement('style');
      style.id = id;
      style.innerHTML = def;
      parent.appendChild(style);
   }
   function removeStyle(parent, id) {
      if (!parent) {
      return;
      }
      var style = doc.getElementById(id);
      if (!style) {
      return;
      }
      parent.removeChild(style);
   }
   addStyle(getParent(), STYLE_ID, style);
   setTimeout(function() {
      removeStyle(getParent(), STYLE_ID);
   }, timeout);
   }(window, document, "body {opacity: 0 !important}", 3000));
</script>