get element by class name with javascript and change it function

HTML

<div class='shared_class'>Hi Im A Shared Class 1</div>
<div class='shared_class'>Hi Im A Shared Class 2</div>
<div class='shared_class mb-3'>Hi Im A Shared Class 3</div>
<button class='btn btn-primary' onclick='change_second_text();'>Change Second Item</button>
<button class='btn btn-primary' onclick="change_any_text(0, 'Moo');">Change 1 (0) to Moo</button>
<button class='btn btn-primary' onclick="change_any_text(2, 'Moo Three!');">Change 3 (2) to Moo Three!</button>

Javascript

// here is a basic version
function change_second_text() {
  var shared = document.getElementsByClassName("shared_class")[1].innerHTML = "<b>Yay i changed...</b>";
}

// here is a function with some more options
// this one you can pass in the item number and the text replace it with on the function
function change_any_text(item_num, text) {
  var shared = document.getElementsByClassName("shared_class")[item_num].innerHTML = text;
}