parent page in iframe

<!DOCTYPE html>
<html>
<head>
<title>iframe - http://stackoverflow.com/questions/11795003/how-to-set-the-src-of-an-iframe-to-the-current-visited-site-using-java-script</title>
<script type="text/javascript">

function load_iframe(addr) {
    var iframe = document.getElementById('iframe1');
    //alert(iframe.src + ' / ' + addr + ' / ' + document.location.href); return;
    if (addr == document.location.href) {
        if (addr.indexOf('?') == -1) {
            addr += '?dummy_string';
        } else {
            addr += '&dummy_string';
        }
    }
    iframe.src = addr;
}

</script>
</head>
<body>
<p>
  <a href="" onclick="event.preventDefault();load_iframe(this.href);">This page</a>
  <a href="http://www.azet.sk" onclick="event.preventDefault();load_iframe(this.href);">Other page</a>
</p>
page content
<iframe id="iframe1" src="" style="width:100%; height:500px" />
</body>
</html>