title: What should be done to make it working in IE7?
body: <p>This code works well in modern browsers. What should be done to make it working in IE7?</p>
  
  <pre><code>function paymentCheck() {
              var obj = {
                              'type' : 'car',
                              'year' : 2008,
                              'make' : 'Dodge',
                              'model' : 'Avenger',
                              'payments' : 'in process',
                              'paid' : 13286,
                              'toBePaid' : 34856,
                              'paymentsLeft' : 24,
              }              
  
              return (obj.toBePaid - obj.paid) / obj.paymentsLeft;
  }
  
  var button = document.getElementById("calcButton");
  button.addEventListener("click", function(){
              alert(paymentCheck());
  }, false);
  </code></pre>