clipboard_js_example.html

<a href="javascript:void(0);" data-clipboard-text="This is the text to copy!" class="btn-copy">
    <span class="m_copy_text">Copy Link</span>
</a>

clipboard_js_example.js

var clipboard = new Clipboard('.btn-copy');
clipboard.on('success', function(e) {

    var trigger = jQuery(e.trigger);
    var text_span = trigger.find('.m_copy_text');
    var text = text_span.text();
    text_span.text('Copied!');
    setTimeout(function () {
        text_span.text(text);
    }, 2000);

});