转载:
http://michaux.ca/articles/lazy-function-definition-patternvar foo = function() { var t = new Date(); foo = function() { return t; }; return foo(); };
var a = {}; a.foo = function() { var t = 5; a.foo = function() { return t++; }; return a.foo(); }; alert(a.foo()); alert(a.foo());