javascript - Why does the variable executes the window object right away and not store it instead? -

i understand what's happening code in variable not stored immediately, instead executed first before can called. example code can (in global scope):

var alertme = alert("i\'m being executed stored called again, why?");

because storing result of calling function, not storing function.

this after:

var alertme = function () {          alert("i\'m being executed stored called again, why?");      };

and when want call it:

alertme();

Th