JS Paste Event
const target = document.querySelector('div.target');
target.addEventListener('paste', (event) => {
let paste = (event.clipboardData || window.clipboardData).getData('text');
paste = paste.toUpperCase();
const selection = window.getSelection();
if (!selection.rangeCount) return false;
selection.deleteFromDocument();
selection.getRangeAt(0).insertNode(document.createTextNode(paste));
event.preventDefault();
});
Modern Mouse