<script "text/javascript">
$().ready(function() {

       $('form').validate({

        rules: {
                    "name": {
                        required: true,
                        minlength: 1
                    }

                     "items": {
                        required: true,
                        minlength: 1
                    }
                },


        highlight: function(element, errorClass) {
            $(element).add($(element).parent()).addClass("invalidElem");
        },
        unhighlight: function(element, errorClass) {
            $(element).add($(element).parent()).removeClass("invalidElem");
        },
        errorElement: "div",
        errorClass: "errorMsg"
    });

});

</script>


<form method="post" action="" id="form" name="form1">
<div class="left-aligned indent">

    <label id="id_label" for="id" class="label">Items:</label>

    <div class="select-group1">

        <input type="checkbox" name="name" value="1" id="item_1"/>
        <label class="checkbox">Item #1</label><br />

        <input type="checkbox" name="items" value="1" id="item_2" />
        <label class="checkbox">Item #2</label><br />

    </div>
</div>