[Please Help]How to write a JS to simulate a mouse click

I have the following elements:

input type=”submit” name=”add” value=”add item” class=”btn btn-add” onclick=”addItem(‘add’);return false;”

I want to write a Javascript to simulate a click of a mouse to add item to my shopping basket I know you can use document.getElementById(‘add’).click() but there’s no Id here

I am very new to this and any help would be much appreciated

Also in #JavaScript _↴