title: use a Variable as a key on JSON
body: <p>my json is like this : 
  `                                              </p>
  
  <pre><code>{
      "isfahan": [
  
      {  
          "id"   : "1",
          "city" : "ahar",                
          "top"  : "35%",
          "left" : "54%"
  
      },
      {  
          "id"   : "2",
          "city" : "marand",              
          "top"  : "35%",
          "left" : "54%"
  
      },
      {  
          "id"   : "3",
          "city" : "miane",               
          "top"  : "35%",
          "left" : "54%"
  
      }
  
  ],
  
  "azerbaijan": [
  
      {  
          "id"   : "3",
          "city" : "miane",               
          "top"  : "35%",
          "left" : "54%"
  
      },
      {  
          "id"   : "3",
          "city" : "miane",               
          "top"  : "35%",
          "left" : "54%"
  
      }
  ],
  
  "ardabil": [
  
      {  
          "id"   : "3",
          "city" : "miane",               
          "top"  : "35%",
          "left" : "54%"
  
      },
      {  
          "id"   : "3",
          "city" : "miane",               
          "top"  : "35%",
          "left" : "54%"
  
      },
      {  
          "id"   : "3",
          "city" : "miane",               
          "top"  : "35%",
          "left" : "54%"
  
      },
      {  
          "id"   : "3",
          "city" : "miane",               
          "top"  : "35%",
          "left" : "54%"
  
      }
  ]
        }
  </code></pre>
  
  <p>and to get JSON object i'm going to use such a this :</p>
  
  <pre><code>                var pulse_state = $('#state_var').html();
  
                  $.getJSON("data/pulse.json").done(function(data){
  
                          localStorage.setItem("data", JSON.stringify(data));
                          $.each(data.isfahan, function(index, value){
  
                              $(".cd-points-container").append(
                                 "&lt;li class='cd-single-point' style='top:"+value.top+"; left:"+value.left+";'&gt;&lt;a class='cd-img-replace' href='#0'&gt;اطلاعات بیشتر&lt;/a&gt;&lt;div class='cd-more-info cd-left'&gt;&lt;h2&gt;"+ value.city + "&lt;/h2&gt;&lt;p&gt;"+ value.sepah_text +"&lt;/p&gt;&lt;a href='#0' class='cd-close-info cd-img-replace'&gt;Close&lt;/a&gt;&lt;/div&gt;&lt;/li&gt;&lt;!-- .cd-single-point --&gt;"
  
                              );
  
                          });
                          //end each function 
  </code></pre>
  
  <p><code>
  </code></p>
  
  <p>as you see if i use <code>data.isfahan</code> to get array , everything is ok but if i change <code>data.isfahan</code> to `data.pulse_state' , it goes wrong !!!!!</p>
  
  <p>i mean i want to use a variable named <code>data.pulse_state</code> and then get JSON object, </p>
  
  <p>could you help me out ?</p>