Extracting info on supported attributes for each element in the single page HTML5 spec.

gistfile1.js

var els = document.querySelectorAll("dl.element");
var attrsList = document.querySelectorAll("dl.element > dt > a[title^='element-'][title$='-attributes']");


function getItemsInAttrList(aList) {
  var r = [];
  r.push(aList.parentNode.parentNode.previousElementSibling.querySelector("code").textContent);
  aList = aList.parentNode;
  while (aList.nextElementSibling && aList.nextElementSibling.nodeName.toLowerCase() == "dd") {
    r.push(aList.nextElementSibling.textContent);
    aList = aList.nextElementSibling;
  }
  return r;
}

for (var i = 0; i < attrsList.length; i++) {
  console.log(getItemsInAttrList(attrsList[i]));
}

/*

["html", "Global attributes", "manifest"]
["head", "Global attributes"]
["title", "Global attributes"]
["base", "Global attributes", "href", "target"]
["link", "Global attributes", "href", "crossorigin", "rel", "media", "hreflang", "type", "sizes", "Also, the title attribute has special semantics on this element."]
["meta", "Global attributes", "name", "http-equiv", "content", "charset"]
["style", "Global attributes", "media", "type", "scoped", "Also, the title attribute has special semantics on this element."]
["script", "Global attributes", "src", "type", "charset", "async", "defer", "crossorigin"]
["noscript", "Global attributes"]
["template", "Global attributes"]
["body", "Global attributes", "onafterprint", "onbeforeprint", "onbeforeunload", "onhashchange", "onmessage", "onoffline", "ononline", "onpagehide", "onpageshow", "onpopstate", "onresize", "onstorage", "onunload"]
["article", "Global attributes"]
["section", "Global attributes"]
["nav", "Global attributes"]
["aside", "Global attributes"]
["h1", "Global attributes"]
["header", "Global attributes"]
["footer", "Global attributes"]
["address", "Global attributes"]
["p", "Global attributes"]
["hr", "Global attributes"]
["pre", "Global attributes"]
["blockquote", "Global attributes", "cite"]
["ol", "Global attributes", "reversed", "start", "type"]
["ul", "Global attributes"]
["li", "Global attributes", "If the element is a child of an ol element: value"]
["dl", "Global attributes"]
["dt", "Global attributes"]
["dd", "Global attributes"]
["figure", "Global attributes"]
["figcaption", "Global attributes"]
["div", "Global attributes"]
["main", "Global attributes"]
["a", "Global attributes", "href", "target", "download", "rel", "hreflang", "type"]
["em", "Global attributes"]
["strong", "Global attributes"]
["small", "Global attributes"]
["s", "Global attributes"]
["cite", "Global attributes"]
["q", "Global attributes", "cite"]
["dfn", "Global attributes", "Also, the title attribute has special semantics on this element."]
["abbr", "Global attributes", "Also, the title attribute has special semantics on this element."]
["data", "Global attributes", "value"]
["time", "Global attributes", "datetime"]
["code", "Global attributes"]
["var", "Global attributes"]
["samp", "Global attributes"]
["kbd", "Global attributes"]
["sub", "Global attributes"]
["i", "Global attributes"]
["b", "Global attributes"]
["u", "Global attributes"]
["mark", "Global attributes"]
["ruby", "Global attributes"]
["rt", "Global attributes"]
["rp", "Global attributes"]
["bdi", "Global attributes", "Also, the dir global attribute has special semantics on this element."]
["bdo", "Global attributes", "Also, the dir global attribute has special semantics on this element."]
["span", "Global attributes"]
["br", "Global attributes"]
["wbr", "Global attributes"]
["ins", "Global attributes", "cite", "datetime"]
["del", "Global attributes", "cite", "datetime"]
["img", "Global attributes", "alt", "src", "crossorigin", "usemap", "ismap", "width", "height"]
["iframe", "Global attributes", "src", "srcdoc", "name", "sandbox", "seamless", "allowfullscreen", "width", "height"]
["embed", "Global attributes", "src", "type", "width", "height", "Any other attribute that has no namespace (see prose)."]
["object", "Global attributes", "data", "type", "typemustmatch", "name", "usemap", "form", "width", "height"]
["param", "Global attributes", "name", "value"]
["video", "Global attributes", "src", "crossorigin", "poster", "preload", "autoplay", "mediagroup", "loop", "muted", "controls", "width", "height"]
["audio", "Global attributes", "src", "crossorigin", "preload", "autoplay", "mediagroup", "loop", "muted", "controls"]
["source", "Global attributes", "src", "type", "media"]
["track", "Global attributes", "kind", "src", "srclang", "label", "default"]
["canvas", "Global attributes", "width", "height"]
["map", "Global attributes", "name"]
["area", "Global attributes", "alt", "coords", "shape", "href", "target", "download", "rel", "hreflang", "type"]
["table", "Global attributes", "border", "sortable"]
["caption", "Global attributes"]
["colgroup", "Global attributes", "span"]
["col", "Global attributes", "span"]
["tbody", "Global attributes"]
["thead", "Global attributes"]
["tfoot", "Global attributes"]
["tr", "Global attributes"]
["td", "Global attributes", "colspan", "rowspan", "headers"]
["th", "Global attributes", "colspan", "rowspan", "headers", "scope", "abbr", "sorted"]
["form", "Global attributes", "accept-charset", "action", "autocomplete", "enctype", "method", "name", "novalidate", "target"]
["fieldset", "Global attributes", "disabled", "form", "name"]
["legend", "Global attributes"]
["label", "Global attributes", "form", "for"]
["input", "Global attributes", "accept", "alt", "autocomplete", "autofocus", "checked", "dirname", "disabled", "form", "formaction", "formenctype", "formmethod", "formnovalidate", "formtarget", "height", "inputmode", "list", "max", "maxlength", "min", "multiple", "name", "pattern", "placeholder", "readonly", "required", "size", "src", "step", "type", "value", "width"]
["button", "Global attributes", "autofocus", "disabled", "form", "formaction", "formenctype", "formmethod", "formnovalidate", "formtarget", "menu", "name", "type", "value"]
["select", "Global attributes", "autofocus", "disabled", "form", "multiple", "name", "required", "size"]
["datalist", "Global attributes"]
["optgroup", "Global attributes", "disabled", "label"]
["option", "Global attributes", "disabled", "label", "selected", "value"]
["textarea", "Global attributes", "autocomplete", "autofocus", "cols", "dirname", "disabled", "form", "inputmode", "maxlength", "name", "placeholder", "readonly", "required", "rows", "wrap"]
["keygen", "Global attributes", "autofocus", "challenge", "disabled", "form", "keytype", "name"]
["output", "Global attributes", "for", "form", "name"]
["progress", "Global attributes", "value", "max"]
["meter", "Global attributes", "value", "min", "max", "low", "high", "optimum"]
["details", "Global attributes", "open"]
["summary", "Global attributes"]
["menu", "Global attributes", "type", "label"]
["menuitem", "Global attributes", "type", "label", "icon", "disabled", "checked", "radiogroup", "default", "command", "Also, the title attribute has special semantics on this element."]
["dialog", "Global attributes", "open"]

*/