Call function at scroll once

Question

I have jQuery function counter and I need to call it when I scroll page

$(document).ready(function () {

    $.fn.counter = function () {
        $(this).each(function () {
            var num = $(this).data('counter');
            var i = 1,
                self = $(this).html(i);
            var interval = setInterval(function () {
                self.html(++i);
                if (i >= num) {
                    clearInterval(interval);
                }
            }, 100);
        });
    };

    $(window).scroll(function() {
        var height = $(window).scrollTop();

        if(height  > 300) {
            $('.counter-1, .counter-2, .counter-3, .counter-4').counter();
        }
    });

});

The problem is when I scroll page again up or down function is called again and again every time.

I tried to use this code

$(document).ready(function () {

    $.fn.counter = function () {
        $(this).each(function () {
            var num = $(this).data('counter');
            var i = 1,
                self = $(this).html(i);
            var interval = setInterval(function () {
                self.html(++i);
                if (i >= num) {
                    clearInterval(interval);
                }
            }, 100);
        });
    };

    $(window).one('scroll', function () {
        var height = $(window).scrollTop();

        if (height > 300) {
            $('.counter-1, .counter-2, .counter-3, .counter-4').counter();
        }
    });

});

but in this case after the reloading the page function is not called.

Is there any way to call function only once on scroll and don't call it again but call it after the reloading the page ?

Answer 1

You should use a name space with .on/.off :

$(window).on('scroll.custom', function () {
    var height = $(window).scrollTop();

    if (height > 300) {
        $('.counter-1, .counter-2, .counter-3, .counter-4').counter();
        $(window).off('scroll.custom')
    }
});