hovercard.js


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// comment out this variable to add your own hovercards
var hovercards = {
    "https://www.w3.org/community/sustyweb/": {"title": "Sustainable Web Design Community Group", "A community group 
dedicated to creating sustainable websites. This group will not publish specifications." }
  };
  
  var article = document.getElementsByTagName("article");

  if (article) {
    article = article[0];
  }

  function hover (target_link) {
    if (hovercards[target_link]) {
      var new_box = document.createElement("div");
      new_box.classList.add("hovercard");
      new_box.innerHTML = hovercards[target_link];
      new_box.style.top = window.scrollY + target_link.getBoundingClientRect().top + "px";
      new_box.style.left = window.scrollX + target_link.getBoundingClientRect().left + "px";
      new_box.id = "tooltip";
      document.body.appendChild(new_box);
    }
  }

  function unhover (target_link) {
    var active_hovercard = document.getElementById("tooltip");

    if (active_hovercard) {
      active_hovercard.parentNode.removeChild(active_hovercard);
    }
  }

  var links = article.getElementsByTagName("a");

  for (var i = 0; i < links.length; i++) {
    links[i].addEventListener("mouseover", function() {
      hover(this);
    });
    links[i].addEventListener("mouseout", function() {
      unhover(this);
    });
    // these handlers are so that the hovercard will appear/disappear
    // with keyboard actions
    links[i].addEventListener("onfocus", function() {
      hover(this);
    });
    links[i].addEventListener("onfocusout", function() {
      unhover(this);
    });
  }