変数への代入は1回で済ます
このJSをどう思う？

var hash = {};
hash["key1"] = "value1";
hash["key2"] = "value2";
hash["key3"] = "value3";

じゃなくて

hash = (function(x) {
x["key1"] = "value1";
x["key2"] = "value2";
x["key3"] = "value3";
return x;
})({});