title: Find key from JSON and compare to value from other JSON object
body: <p>I'm making an advanced search function in my online video library. I get the information about the movies from the JSON-file object movies_object, and searching for the director, name of movie, country and actors works well. My problem is when I'm searching for genres. Genres is stored in a seperate JSON-file object, genres_object. </p>
  
  <p>My problem is that I can't figure out how to find the key name in genres_object! I have the values, but I cant figure out how to find the keys. I have to do this so that the right genre goes to the right movie. </p>
  
  <p>Here is my javascript function for advanced search </p>
  
  <pre><code>function advanced_search(){
  var genres = genres_object;
  var searchParameters = get_query_string_parameters();
  
  for(movies in movies_object){
  var found1 = false;
  var found2 = false;
  var found3 = false;
  var found4 = false;
  var found5 = false;
  
  var id = movies_object[movies].id;
  
  
  if(movies_object[movies].otitle.toLowerCase() == 
  searchParameters.film_title.toLowerCase() || 
  isEmpty(searchParameters.film_title)) {
  found1 = true;
  }
  
  if(movies_object[movies].folk) {
  if(movies_object[movies].folk.toLowerCase().includes(searchParameters.actor.toLowerCase()) || isEmpty(searchParameters.actor)) {
  found2 = true;
  }
  }
  
  //This is the part I'm having trouble with
  if(genres_objects[movies] == movies_object[movies].id){
    for(var i = 0; i &lt; genres_object[movies].length; i++){
  if((genres_object[movies[i]]).includes(searchParameters.genre.toLowerCase())){
  found5 = true;
  }
  }
  } 
  
  
  if(found1 &amp;&amp; found2 &amp;&amp; &amp;&amp; found5) {
  console.log(movies_object[movies]); 
  results.push(movies_object[movies]);
  
  }
  display_X(results);
  }
  }
  </code></pre>
  
  <p>And here is the format for the JSON movie objects:</p>
  
  <pre><code>movies_object={"1080": {"year": 1957, "otitle": "Ni liv", "youtube trailer id": "", "ntitle": "Ni liv", "mod_date": null, "length": 91, "id": 1080, "keywords": null, "reg_date": null, "description": "Jan Baalsrud er p\u00e5 et sabotasjeoppdrag fra England til Norge med 11 a", "dir": "Arne Skouen", "etitle": "Nine Lives", "country": "NOR", "imdb_id": "", "folk": "Jack Fjeldstad, Henny Moan, Lydia Op\u00f8ien, Edvard Drabl\u00f8s"},
  </code></pre>
  
  <p>Lastly, the format of the JSON genres:
      genres_object={"3734": ["komedie"], "3724": ["sci-fi"],</p>
  
  <p>Thanks in advance!</p>