generate.html

<?xml version="4.0" encoding="UTF-8"><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
  <title>Tig cheat sheat</title>
  <meta content="text/html; charset=UTF-8" http-equiv="Content-Type" />
</head>
<body>

<form method="post" action="https://tex.mendelu.cz/en/" enctype="multipart/form-data">

<textarea name="pole" id="latexText" style="display:none;" ></textarea>
<input type="hidden" name="preklad" value="latex" />
<input type="hidden" name="pruchod" value="1"/>
<input type="hidden" name="pdf" value="PDF" />
<p style="text-align: center">
<input id="btnGenerate" type="submit" value="Generate the last version of the 'tig cheat sheat'!" disabled="true" />
</p>
<p style="text-align: center">
Note: Due to the fact that the generation is done by a third party website ( https://tex.mendelu.cz/en/ ), <br/>
your browser should warn you that the page attempts a 'cross-script scripting (XSS)'. <br/>
If you really want to generate the cheat sheet, you will have to ignore the warning and to continue... ;) 
</p>
</form>
  <script>
   var xmlhttp = new XMLHttpRequest();
   xmlhttp.onreadystatechange = function() {
        if (xmlhttp.readyState == XMLHttpRequest.DONE ) {
           if(xmlhttp.status == 200){
               document.getElementById("latexText").innerHTML = xmlhttp.responseText;
               document.getElementById("btnGenerate").disabled = false;
           }
           else if(xmlhttp.status == 400) {
              alert('There was an error 400')
           }
           else {
               alert('something else other than 200 was returned')
           }
        }
    }

    xmlhttp.open("GET", "http://raw.githubusercontent.com/pmiossec/tig-cheat-sheet/master/tig-cheat-sheet.tex", true);
    xmlhttp.send();
    </script>
</body>
</html>