title: how to get json object titles
body: <p>I'm a new programmer , I know how to use dictionary/JSON to get the value of whatever you want like for example <code>var x = {"name":jack,"age":20};<br>
  then x.name = jack</code></p>
  
  <p>but what if I've a table that has been imported through an unknown EXCEL file and I just want to know the title of each column , how can i do that ? </p>
  
  <p>for example </p>
  
  <pre><code>Var table = [{"id":0 , "name":jack,"age":25,"profession":student},{"id":1 , "name":nora,"age":22,"profession":student}]
  </code></pre>
  
  <p>i want to make a javascript function that can inform me with titles of each columns , the number of the columns 
  how can i do that ?</p>