Create an element once in a jquery plugin

I've written quite a few jQuery plugins in the past and this problem has come up a couple times now. Usually I just create a global variable outside the closure and call it a day. This time I'm trying to figure out what the proper way of doing it is.

So here's the deal. I have my base plugin setup like this:

(function($) {
  $.fn.nameOfPlugin = function(options) {
    var defaults = {
        foo: 'foo'
    }
    var opts = $.extend(defaults, options);

    re开发者_运维技巧turn this.each(function(){
        //if first time through call create
    });
  };

  function create() {
    //create stuff here only once
    $('body').append("<div id='plugin_overlay'></div>");
  };

})(jQuery);

and obviously I would initate it like this:

$('.class').nameOfPlugin({foo:'bar'});

Since I am using a class as a selector return this.each could run anywhere from 1 to 50 times. What is the best way to run the create method only once per selector?

I realize that in this situation I can simply check:

$('#plugin_overlay').length > 0

but I will be adding a timestamp at the end of the id so it is unique based on the selector.

I do have a couple more ideas onto what I can do, im just wondering what is the best way to do this.

---

I may be completely misunderstanding the question here, but if you only want to call the method once per selector, why not just call it prior to the each?

create();

return this.each(function(){
   ...
});

Alternatively, you can use the index parameter which is passed to the each function:

return this.each(function(i){
   if(i==0) create();
   ...
});