JavaScript ESC key listener

ESC-handler.js

// document is necessary; window context requires a click into the page body for it to work (at least in Chrome)

document.addEventListener('keydown', function(e){
    if((e.key=='Escape'||e.key=='Esc'||e.keyCode==27)){ // if necessary: target specific node with: && (e.target.nodeName=='BODY')
        // if necessary: e.preventDefault();
        // do something with the ESC button press, i.e. close modal/NAV/lightbox etc.
    }
}, true);