Am I creating a memory leak?

Am I creating a memory leak?

  2. function Widget(){
  3.       this.myfield = $('#id_myfield');      
  4.       var clickHandler = function(event){ //do something };      
  5.       this.myfield.bind('click', clickHandler);
  6. }

  8. myWdgt = new Widget();

I was reading https://developer.mozilla.org/en/a_re-introduction_to_javascript and I was not sure if this applied using jQuery also.

I have made it a habit to try to only query the DOM once for performance reasons. Now I'm not sure if I'm creating a memory leak by doing so. 

Should I be utilizing the window.unload event to explicitly delete my object instances?

Thanks
Josh