title: How to loop through a json array in Flask by javascript?
body: <p>There is a json array in my html passed from Flask. But when I try to use <code>javascript</code> to loop through it, it seems like I can only get the subscript of array. The results display as <code>0,1,2...</code> kind of thing. How can I get the value of json array instead of the subscript?</p>
  
  <p>Json Array:</p>
  
  <pre><code>json_array = ["EPGD", "KEGG"]
  </code></pre>
  
  <p>Javascript code:</p>
  
  <pre><code>for (var item in json_array){
      alert(item);
  }
  </code></pre>