[devote]

<a href="http://blatest.ru">link to blatest.ru</a>

<script type="text/javascript">

var anchors = document.getElementsByTagName('A'),
     found = false;

for( var i = 0; i < anchors.length; i++ ) {
    if ( /http:\/\/test\.ru/ig.test( anchors[i].href ) ) {
        found = true;
    }
}

if ( !found ) {
    alert( 'fail' );
}
</script>