test.html

<script>
function A() {
  alert("new A called");
  this.my_method = function(element) {
    alert("a#method called");
  }
};

A.initialize = function() {
    alert ("A#initialize called");
  return function() {
    alert ("A#initialize returned obj called");
  };    
}

a=new A(); /* new A called */
a.my_method() /* => a#method called*/
obj=A.initialize(); /* => A#initialize called*/
obj(); /* => A#initialize returned obj called*/
</script>