遍历object中所有key

http://stackoverflow.com/a/921808/2177408

for (var key in validation_messages) {    // skip loop if the property is from prototype    if (!validation_messages.hasOwnProperty(key)) continue;    var obj = validation_messages[key];    for (var prop in obj) {        // skip loop if the property is from prototype        if(!obj.hasOwnProperty(prop)) continue;        // your code        console.log(prop + " = " + obj[prop]);    }}