Ext permission settings button

getClass:function(v ,metadata ,record ,rowIndex ,colIndex ,store ){
 var dutyStage = STORE.getAt(rowIndex).get('XXX')；//获取表格列
 var flag = false;
 Ext.Ajax.request({
 url:‘action.do',
 method:'POST',
 async:false,
 success:function(response){
 var text = response.responseText;
 if(text == "true"){
 flag = true;
 }
 }
 })
 if(flag){
 return 'x-hidden';
 }
}