Safari is throwing an error when i click the button "ReferenceError: Can't find variable: togglePopUp"
The function works fine in every other Browser (including IE)
Do you have any suggestions whats going on?
var formPopUp = document.querySelector('.form-popup');
var modalOpen = false;
var togglePopUp = function togglePopUp() {
  modalOpen = !modalOpen;
  formPopUp.classList.toggle('active');
  if (modalOpen) {
    document.querySelector('body').style = "overflow : hidden;";
  } else {
    document.querySelector('body').style = "overflow : auto;";
  }
};
var close = document.querySelector('.form-popup .close');
close.addEventListener('click', function () {
  togglePopUp();
});
window.onclick = function (event) {
  if (event.target == formPopUp) {
    togglePopUp();
  }
};
<button class="btn" onclick="togglePopUp()">Click</button>
 
    