MXGraph get cell value not taking latest HTML

I'm trying to persist MXGraph to DB and re generate upon user request. Below is how use user flow is:

• Created HTML for Vertex


• Added vertex (v) to Graph


• select HTML element (v.getElementById())


• modify HTML in (V) vertex


• 
  

  get XML of graph. Here is Code Snippt im usig to create XML

  
  

  
  

  
  var enc = new mxCodec(mxUtils.createXmlDocument());
  var node = enc.encode(_editor.graph.getModel());
  var xml = mxUtils.getPrettyXml(node);
  
  

  
  


• 
  

  persist it to DB

  
  

From above, i'm able to HTML of vertex in Step:1 but not after step:3. But, im sure that i'm trying above code snippet after modifying DOM in STEP:3.

Please let me know how to save data what's there currently in a Vertex.