Ext json取值问题

[kkobebryant]

var start = ‘’;

var taskStore = Ext.create("Gnt.data.TaskStore", {

model : 'Gnt.model.Task',
autoLoad : true,

proxy : {
type : 'ajax',
method : 'GET',
//url : '/gantt/gantt-print/tasks.js',
url : '/ganttReport/getProjectJson.jsp?key='+mkey,
reader : {
type : 'json'
}
}

});

json返回值:[{"Responsible":"","Name":"123","BaselinePercentDone":0,"EndDate":"2016-06-02","StartDate":"2016-05-27","BaselineEndDate":"2016-06-02","PercentDone":0}]

请问怎么写可以将json里的值StartDate赋值给外面的变量start？

[Go 旅城通票]

http://bbs.csdn.net/topics/391962503 看1#，不是回复过了，还需要注意model要和数据源一致