Get captions (subtitles) from a given YouTube video

Attempt to answer this question: https://stackoverflow.com/q/52312802/4092887

by rwhal06

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
<div id="demo"><i>Loading captions...</i></div>

JavaScript

$.ajax({
  type: "GET",
  url: "https://video.google.com/timedtext?type=track&v=_ryxuehnp8k&id=0&lang=en",
  crossDomain: true,
}).done(function(data) {
  console.log(data);
  getCaption(data);
});


var parser, xmlDoc;
var HTML_captions = "";

// Parse the AJAX response and get the captions.
function getCaption(ajax_response) {
  try {

    parser = new DOMParser();
    xmlDoc = parser.parseFromString(ajax_response, "text/xml");
    //console.log(ajax_response);
    //console.log(xmlDoc.getElementsByTagName("transcript").length);

    if (xmlDoc.getElementsByTagName("transcript").length > 0) {
      // Loop the results of the xmlDoc:
      for (var i = 0; i < xmlDoc.getElementsByTagName("transcript")[0].childNodes.length; i++) {
        console.log(xmlDoc.getElementsByTagName("transcript")[0].childNodes[i].innerHTML);
        HTML_captions += xmlDoc.getElementsByTagName("transcript")[0].childNodes[i].innerHTML + "<br/>";
      }
    } else {
      // Loop the results of the ajax_response;
      for (var i = 0; i < ajax_response.getElementsByTagName("transcript")[0].childNodes.length; i++) {
        console.log(ajax_response.getElementsByTagName("transcript")[0].childNodes[i].innerHTML);
        HTML_captions += ajax_response.getElementsByTagName("transcript")[0].childNodes[i].innerHTML + "<br/>";
      }
    }

    document.getElementById("demo").innerHTML = "<i>Preparing captions...</i>";
    setTimeout(fillData(), 2000);

  } catch (err) {
    console.log(err);
    alert('Error at getCaption function - see console form more details.');
  }
}


// Fill the data "captions" in a HTML "div" control.
function fillData() {
  try {
    document.getElementById("demo").innerHTML = HTML_captions;
  } catch (err) {
    console.log(err);
    alert('Error at fillData function - see console form more details.');
  }

}