You can use number as function/variable name, the numberic name can't be accessed from parent scope, but can be accessed by 'this' in private scope.
var o=
{
attr1:'value of attr1',
1:'private attr ,the index is 1',
301:function(){
console.log('private function , name is 2');
},
fun1:function(){
console.log(this[1]);
this[301].call(this);
}
}; o.fun1();