js解析json，js转换json成map,获取map的key,value

json串格式

{
   "10.10.11.1": {
        "target_1": "34.2",
        "target_3": "70.83",
        "target_2": "50.51",
        "target_5": "110.68",
        "c_event": "event",
        "target_4": "90.79",
        "c_timestamp": "12:54:34",
        "target_6": "10.2",
        "c_subject": "10.18.11.0"
    }
}

{string,map<String,String>}类似这样的格式

js函数：

function getValue(){
		var str = '{ "10.10.11.1": { "target_1": "34.2","target_3": "70.83","target_2": "50.51"}}';
		var map = eval（"("+str+")");
		for (var key in map) {  
		var a = map[key];
		for (var k in a) {  
			alert(k+'---'+a[k]);
		}   
  }  
}

思路：现将json串，解析为map对象，可是在chrome浏览器不支持。