recordar selecciones de botones de radio

Tengo el siguiente código que funciona perfectamente. Le permite al usuario 'me gusta' o 'no me gusta' cada publicación con botones de radio. Las casillas de verificación son interruptores que permiten al usuario mostrar / ocultar todas las publicaciones que le gustaron o no.

El problema es que necesito que la página recuerde las selecciones de los botones de opción cuando el usuario se va y regresa. ¿Esto requeriría cookies? Si es así, ¿cómo lo implemento?

    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <title>Unhide on checkboxes/radio buttons</title>
    <link rel="stylesheet" type="text/css" href="_styles.css" media="screen" />
    <script type="text/javascript">

function radioGroupValue(groupObj)
{
    //Check if there is only one option (i.e. not an array)
    if (!groupObj.length)
    {
        return (groupObj.checked) ? groupObj.value : false;
    }

    //Multiple options, iterate through each option
    for (var i=0; i<groupObj.length; i++)
    {
        if (groupObj[i].checked)
        {
            return groupObj[i].value;
        }
    }

    //No option was selected
    return false;
}


function toggleLayer(formObj)
{
    var showLikes = document.getElementById('show_likes').checked;
    var showDislikes = document.getElementById('show_dislikes').checked;

    var postIndex = 1;
    while(document.getElementById('post_'+postIndex))
    {
        var liked = radioGroupValue(formObj.elements['like_'+postIndex])
        var display = ((!showLikes && liked==='1') || (!showDislikes && liked==='0')) ? 'none' : '';
        document.getElementById('post_'+postIndex).style.display = display;
        postIndex++;
    }
}
</script>
</head>
<body>

<form action="" method="post">
    <fieldset>
        <legend>Unhide Layer Form</legend>
        <ul>
            <p><input id="show_likes" name="show_likes" type="checkbox" value="1" checked="checked" onclick="toggleLayer(this.form);" /><label for="b1">Show Likes:</label> </p>
            <p><input id="show_dislikes" name="show_dislikes" type="checkbox" value="1" checked="checked" onclick="toggleLayer(this.form);" /><label for="b1">Show Disikes:</label> </p>
        </ul>

    <label>Email:</label>

        <input type="email" />  
    </fieldset>
<br><br>

    <fieldset>
        <legend>Posts</legend>

<div id="post_1" class="post">
    <b>Post #1</b><br>
    Content of post #1<br>
    <p><input type="radio" name="like_1" value="1"><label for="like1a">Like</label></p> <p><input type="radio" name="like_1" value="0" onclick="toggleLayer(this.form);"><label for="like1b"> Dislike</label></p>
</div>
<div id="post_2" class="post">
    <b>Post #2</b><br>
    Content of post #2<br>
    <p><input type="radio" name="like_2" value="1"><label for="like2a">Like</label></p> <p><input type="radio" name="like_2" value="0" onclick="toggleLayer(this.form);"><label for="like2b"> Dislike</label></p>
</div>
<div id="post_3" class="post">
    <b>Post #3</b><br>
    Content of post #3<br>
    <p><input type="radio" name="like_3" value="1"><label for="like3a">Like</label></p> <p><input type="radio" name="like_3" value="0" onclick="toggleLayer(this.form);"><label for="like3b"> Dislike</label></p>
</div>
<div id="post_4" class="post">
    <b>Post #4</b><br>
    Content of post #4<br>
    <p><input type="radio" name="like_4" value="1"><label for="like4a">Like</label></p> <p><input type="radio" name="like_4" value="0" onclick="toggleLayer(this.form);"><label for="like4b"> Dislike</label></p>
</div>
<div id="post_5" class="post">
    <b>Post #5</b><br>
    Content of post #5<br>
    <p><input type="radio" name="like_5" value="1"><label for="like5a">Like</label></p> <p><input type="radio" name="like_5" value="0" onclick="toggleLayer(this.form);"><label for="like5b"> Dislike</label></p>
</div>
<div id="post_6" class="post">
    <b>Post #6</b><br>
    Content of post #6<br>
    <p><input type="radio" name="like_6" value="1"><label for="like6a">Like</label></p> <p><input type="radio" name="like_6" value="0" onclick="toggleLayer(this.form);"><label for="like6b"> Dislike</label></p>
</div>
<div id="post_7" class="post">
    <b>Post #7</b><br>
    Content of post #7<br>
    <p><input type="radio" name="like_7" value="1"><label for="like7a">Like</label></p> <p><input type="radio" name="like_7" value="0" onclick="toggleLayer(this.form);"><label for="like7b"> Dislike</label></p>
</div>
</form>

¿Algún puntero?

Respuestas a la pregunta(3)

Su respuesta a la pregunta