How to convert variable name to string in JavaScript?

var a = 1, b = 2, c = 'hello';
var array = [a, b, c];

var obj = {
    'a': 1,
    'b': 2,
    'c': 'hello'
};

for (var name in obj){
    alert(name);
    alert(obj[name]);
}

alert(obj.a);
alert(obj.c);

var hash = {};
hash.a = 1;
hash.b = 2;
hash.c = 'hello';
for(key in hash) {
    // key would be 'a' and hash[key] would be 1, and so on.
}