var productsCountController = new function(){
    "use strict";
    var self = this;
    function addEvents(){
        var menuElements = document.querySelectorAll("input.buyAmount");
        for (let i = 0; i < menuElements.length; i++){
            menuElements[i].lastNumber = menuElements[i].value;
            menuElements[i].addEventListener('input', function () {self.check(this)});
        }
    }
    addEvents();
    this.check = function(element){
        if (element.value.length > 1 && element.value.charAt(0) === '0'){
            element.value = element.value.slice(1,6); 
        }
        if (element.value.length > 6) {
            element.value = element.lastNumber;
        } else {
            element.lastNumber= element.value;
        }
    };
};