[javascript] 라디오버튼(radio)

function check_form2(form) {
    var goods_5_l = form.goods_5.length;
    var goods_5 = "";
    for (var i = 0 ; i < goods_5_l; i++) {
        if(form.goods_5[i].checked == true)    goods_5 = form.goods_5[i].value;
    }
    alert(goods_5);
}
 
<form onsubmit="return check_form2( this );">
    <div class="customer_info">
        <p class="mgr_40" style="padding-top:10px;"><strong>응모상품 선택</strong> <label class="skip">응모상품 선택</label></p>
        <p style="font-size:18px; font-weight:bold; padding-top:10px;">
            <span style="padding-right:40px;">
                <input type="radio" name="goods_5" value="1" checked="checked"/> 
                <img style="padding-left:10px;" src="../images/passion_cam/img_g1.gif" alt="커피쿠폰" /> (커피쿠폰)
            </span> 
            <span>
                <input type="radio" name="goods_5" value="2"/> 
                <img style="padding-left:10px;" src="../images/passion_cam/img_g2.gif" alt="멀티탭" /> (멀티탭)
            </span>
        </p>
    </div>
</form>