title: in extjs4 how to get and access uploaded file's contents
body: <p>i am working in extjs4 on file upload functionality. i have coded view as-</p>
  
  <pre><code>Ext.define('Balaee.view.kp.dnycontent.Content', 
  {
      extend:'Ext.form.Panel',
      requires:[
                'Balaee.view.kp.dnycontent.ContentView'
                ],
      id:'ContentId',
      alias:'widget.Content',
      title:'This day in a history',
      items:[
  
      {
          xtype: 'fileuploadfield',
          hideLabel: true,
          emptyText: 'Select a file to upload...',
          //inputType: 'file',
          id: 'upfile',
          //name:'file',
      width: 220
  }],
  
     buttons: [{
          xtype : 'button',
          fieldlabel:'upload',
          action:'upload',
          name:'upload',
          text: 'Upload',
          formBind:'true'
  
      }]
  });
  </code></pre>
  
  <p>And in controller to get file i had written code as-</p>
  
  <pre><code>getUpload : function() {
          var fileobj = Ext.getCmp('upfile');
  
          var file10 = Ext.getCmp('ContentId').getEl().down('input[type=file]').dom.files[0];
  
          var reader = new window.FileReader();
          reader.onload = function(oFREvent) {
              fileobj=oFREvent.target.result;
              console.log(oFREvent.target.result);
  
          };
  
  
          var storeObj=this.getStore('kp.DnycontentStore');
           console.log(storeObj);
           storeObj.load({
           params:{
           data:file
           },
           callback: function(records,operation,success){
             console.log("send");
           },
           scope:this
           })
           console.log(storeObj);
  
      }
  });
  </code></pre>
  
  <p>So above "  var file10 = Ext.getCmp('ContentId').getEl().down('input[type=file]').dom.files[0];" line is retriving all the file related data as- <code>"File{size=879394,type="image/jpeg",name="Chrysanthemum.jpg", more...}"</code>
  So how to get and access actual contents of uploaded file? Please help me</p>