Why are JS functions not being called on iPhone 4?

Question

JavaScript

Today, for the first time, I encountered such a problem: on the iPhone 4 (9.3.5) and iPad 2 (8.2), the functions I created are not called. At the same time, everything works clearly in the iPhone 5S (10.0.1).
Works:

<button type="button" onclick="alert('test')">test</button>

<script>
    $('#test').on('click', function(){alert('test')};
</script>
<button type="button" id="test">test</button>

Does not work:

<script>function test() {alert('test');}</script>
<button type="button" onclick="test()">test</button>

<script>var test = function () {alert('test');}</script>
<button type="button" onclick="test()">test</button>

<script>
    $('#test').on('click', function(){
        test();
    };
    function test() {alert('test');}
</script>
<button type="button" id="test">test</button>

Answer 1

click is for mice.
tap event on phones, maybe that's why it doesn't work

Answer 2

function(e) {
      event.preventDefault();

Doesn't make you think?