防止js文件被调用两次

Question

有没有办法将变量放在javascript文件中，以便在调用文件时它会递增（如Java中的static var）？我想用它来防止两次调用js文件。或者，还有另一种方法吗？

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!');
}