Read More link when someone copy your article

functions.php

<?php 

/* Do Not copy open php tag */

/**
* @author    Hunk Riyaz
* @link      http://extracatchy.net
*/
function add_copyright_text() {
    if (is_single()) { ?>

<script type='text/javascript'>
function addLink() {
    var selection = window.getSelection();

    var htmlDiv = document.createElement("div");
    for (var i = 0; i < selection.rangeCount; ++i) {
        htmlDiv.appendChild(selection.getRangeAt(i).cloneContents());
    }
    var selectionHTML = htmlDiv.innerHTML;

    var pagelink = "<br/><br/>Read more at ExtraCatchy: <a href='"+document.location.href+"'>"+document.location.href+"</a>";
    var copytext = selectionHTML + pagelink;
    
    var newdiv = document.createElement('div');
    newdiv.style.position = 'absolute';
    newdiv.style.left = '-99999px';
    
    document.body.appendChild(newdiv);
    newdiv.innerHTML = copytext;
    selection.selectAllChildren(newdiv);
    window.setTimeout(function () { document.body.removeChild(newdiv); }, 0);
}
document.oncopy = addLink
</script>

<?php
}
}

add_action( 'wp_head', 'add_copyright_text');

going to make tutorials of this code at my website http://extracatchy.net