Running scripts from Greasemonkey4IE

Is there any way to call a meth开发者_JS百科od defined in my .js file (the one I will load into greasemonkey) automatically? what I mean by automatically is I don't want to create an html file to call that... Is there some way to use use "script" tags without creating html file. Here I am trying to create a simple UI with a button for example.

The code to create the button will be in the .js file.

Any ideas ??? Thanks

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Do you mean:

(function(){
   // gets executed immediately
})();