Takes an array (or uses all but the first parameter as an array) of keys and returns a new object containing all of the values with the specified keys.

getProps.js

function getProps(obj, keys) {
    var ret = {};
    keys = ret.toString.call(keys) == '[object Array]'
        ? keys
        : [].slice.call(arguments, 1);
    for (var key, i = keys.length; i--;) {
        key = keys[i];
        ret[key] = obj[key];
    }
    return ret;
}