title: how could i change the value, named bytecnt
body: <pre><code>items: [{
      rowspan:3,
      columnWidth: 0.5,
      margin: '10 10 10 10',
      xtype: 'fieldset',
      title:'SMS',
      enableKeyEvents: true,
      items: [{
          xtype:'textarea',
          width: 200,
          height: 160,
          id: 'content',
          value: '',
          enableKeyEvents: true,
          listeners: {
              keyup: function(form, e) {
              var cnt2;
              var len2;
              var han2;
              var varCont;
              len2 = 0;
              han2 = 0;
              varCont = this.value;
  
              for( cnt2 = 0 ; cnt2 &lt; varCont.length; cnt2++ ){
                  if( varCont.charCodeAt(cnt2) &gt; 255 ){
                      len2 += 2;
                      han2 += 2;
                  }else{
                      len2 ++;
                  }
              }
              Ext.getCmp('bytecnt').setValue(len2);  //here is problem 
              }//keyup
          }//listener
  
      },{
          xtype:'text',
          html:"&lt;input id='bytecnt' name='bytecnt' width='20' value='1'&gt;",
          width: 200,
          height:20
      }]
  </code></pre>