Preventing a js file from being called twice

Question

Is there a way to put a variable in a javascript file so that it increments whenever the file is called (like a static var in Java)? I want to use it to prevent calling a js file twice. Or, is there another way to do this?

Answer 1

var checkit = window.check_var;

if(checkit === undefined){ //file never entered. the global var was not set.
    window.check_var = 1;
}
else {
    alert('FILE WAS CALLED ALREADY!');
}