Static variables in JavaScript

Question

How can I create static variables in Javascript?

Answer 1

Working with MVC websites that use jQuery, I like to make sure AJAX actions within certain event handlers can only be executed once the previous request has completed. I use a "static" jqXHR object variable to achieve this.

Given the following button:

Action!

I generally use an IIFE like this for my click handler:

var ajaxAction = (function (jqXHR) {
    return function (sender, args) {
        if (!jqXHR || jqXHR.readyState == 0 || jqXHR.readyState == 4) {
            jqXHR = $.ajax({
                url: args.url,
                type: 'POST',
                contentType: 'application/json',
                data: JSON.stringify($(sender).closest('form').serialize()),
                success: function (data) {
                    // Do something here with the data.
                }
            });
        }
    };
})(null);