Internal Clipboard (JS only)

HTML

<a href="#" onclick="CopyURLToClipboard()">copy</a>

JavaScript

function CopyURLToClipboard() {
alert('test');
     var inp = document.createElement('input');
    inp.value = "Testing Testing";
    document.body.appendChild(inp);
    inp.select();
    document.execCommand('copy');
    inp.remove();

    return true;
}