JS 獲取JSON格式數據對象值

應用場景：與ArcGIS Server 服務通訊，添加feature對象後，返回JSON格式數據，獲取添加成功後的OBJECTID.

<span style="white-space:pre">		</span>var json;
		//var str = {"code":0,"data":[{"uid":"689791","username":"vaghyuzhihao","orgid":"627","status":"1","subname":"yuzhihao","roleids":"1","orgcode":"600251","name":"yuzhihao","mapid":"0","passwd":"","siteid":"0","createorgcode":"600251","alarmview":"0"}]};
		//var str = {"code":0,"data":[{"uid":"689791","alarmview":"0"}]};		
		var str = {"code":0, "addResults": [ { "objectId": "120555935", "success": "true" } ] };
		if(typeof str === 'object'){
		    json = str;
		}
		else{
		    json = eval(str);// 如果打印不成功 此處改爲  eval("("+str+")");
		}
		alert(json.addResults[0].objectId);