fetch("https://api.thecatapi.com/v1/images/search").then(function(r)
    {
     if (r.status != 200) {
        alert('Error: unable to load preview, HTTP response '+r.status+'.');
      return
     }
     r.text().then(txt => console.log(txt))
    }).catch(function(err) {alert('Error: '+err);});