JSFiddle - React, Tailwind, and code Playground

HTML

<input name="" type="checkbox" value="here"/>(if this was checked)
<input name="" type="checkbox" value="here"/>(then this)
<input name="" type="checkbox" value="there"/>(would not allow prompt alert) 
<input name="" type="checkbox" value="here"/>(would allow)

JavaScript

$(':checkbox').change(function() {
    if (this.checked) {
        var lastChecked = $(this).prevAll(":checked:first");
        if (this.value == lastChecked.val()) {
            alert("previous checked box has same value");
        }
    }
});