gistfile1.txt

function createTOC() {
  var list = document.getElementByTagName("UL")[0];
  var headingText
  var TOCEntry
  for (i = 0; i <= 10; i++) {
    headerText = document.getElementById(i).innerHTML;
    TOCEntry = document.createElement("li")
    TOCEntry.innerHTML = "<a href=#" + i + ">" + headingText + "</a>";
    list.appendChild(TOCEntry);
  }
}
document.addEventListener("DOMContentLoaded", function(event) { 
  createTOC();
})