Calculators.js

ui = {

   initPage: function () {

       console.log("Calculators Script loaded");

       //Calculator
       var amountsArray = [];
       $('.item_number').each(function(index, element){
           amountsArray[index] = parseInt($(element).text);
       })
       if(isNaN($("#input_amount") && $("#input_amount").value > 0)){
           var inputValue = $('input_amount').value;
           $('.item_number').each(function(index, element){
               $(element).text = amountsArray[index] * inputValue;
           })
       }else{
           $('.item_number').each(function(index, element){
               $(element).text = amountsArray[index];
           })
       }
   },
   
 init: function () {
       ui.initPage();
   }

}

ui.init();