팁

http://stackoverflow.com/questions/5767325/how-to-remove-a-particular-element-from-an-array-in-javascript

First, find the index of the element you want to remove:

var array = [2, 5, 9];
var index = array.indexOf(5);

Note: browser support for indexOf is limited; it is not supported in Internet Explorer 7 and 8.

Then remove it with splice:

if (index > -1) {
    array.splice(index, 1);
}

http://stackoverflow.com/questions/3068534/getting-javascript-object-key-list

객체 키만 가지고 배열 만들기

Object.keys(obj); // ['key1', 'key2', 'key3', 'key4']

https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Date

날짜 객체