const classes = ['data', 'par', 'opt'];
classes.some(c => block.includes(c));
document.addEventListener('click', e => {
const type = e.target.closest('[data-type]')?.dataset.type;
if (type) {
console.log(type.replace(/\d/g, ''));
}
});
// или
document.querySelectorAll('[data-type]').forEach(function(n) {
n.addEventListener('click', this);
}, e => console.log(e.currentTarget.dataset.type.match(/\D+/)[0]));
<form action="demo_form.asp" onsubmit="myFunction()">
<input type='hidden' name='mess' id='mess'>
<div name='mess_s' id='mess_s' class='f_ot' contenteditable='true'>blabla</div>
Enter name: <input type="text" name="fname">
<input type="submit" value="Submit">
</form>
<script>
function myFunction() {
document.getElementById('mess').value=document.getElementById('mess_s').innerHTML;
document.getElementById('mess_s').innerHTML = '';
}