function onBeforeShow() {
    var trigger = self.hc_.getAnchorElement();
    var ch = self.getChar_(trigger);
    if (ch) {
      goog.dom.setTextContent(self.zoomEl_, self.displayChar_(ch));
      goog.dom.setTextContent(self.unicodeEl_, goog.i18n.uChar.toHexString(ch));
      // Clear the character name since we don't want to show old data because
      // it is retrieved asynchronously and the DOM object is re-used
      goog.dom.setTextContent(self.charNameEl_, '');
      self.charNameFetcher_.getName(ch, function(charName) {
        'use strict';
        if (charName) {
          goog.dom.setTextContent(self.charNameEl_, charName);
        }
      });
    }
  }
Function called by hover card just before it is visible to collect data.