Vanilla JS onclick copy w/ fallback

let b= document.querySelector('pre'),
    c= 'i am stupid';

b.addEventListener('copy',
function(e){
e.clipboardData.setData('text', c);
e.preventDefault();
});

b.onclick= function() {
try{ navigator.clipboard.writeText(c);
alert('Copied!');
}
catch(err){
    try{let inp =document.createElement('input');
        document.body.appendChild(inp)
        inp.value= c; inp.select();
        document.execCommand('copy',false);
        inp.remove();
        alert('Copied!!');}
    catch(err){
        try{let e= window.getSelection(),
            f= document.createRange();
            f.selectNodeContents(b);
            e.removeAllRanges();
            e.addRange(f);
            document.execCommand("copy");
            alert('Copied!!!');}
         catch(err){alert("Couldn't copy because: "+ err.message)}
     }
}
};