Well, I came up with this, which I don’t know if it is the best solution but it works:
<script>
var selectFunction = function() {
document.getElementsByClassName('cat-item cat-item-19')[0].getElementsByTagName("label")[0].innerHTML = '<input type="checkbox" name="oftipodevideo[]" value="19"> Live';
document.getElementsByClassName('cat-item cat-item-20')[0].getElementsByTagName("label")[0].innerHTML = '<input type="checkbox" name="oftipodevideo[]" value="20"> Official';
};
selectFunction();
</script>
Thanks for your help.