<script type="text/javascript">
function check() {

    var str = '';
    
    var rds = document.getElementsByTagName("input");
    
    var radios = new Array;
    radios[0] = new Array();
    
    var j = 0;
    var k = 0;
    
    for(i = 0; i < rds.length; i++) {
        
        if(rds[i].type=="radio") {
            
            if(k > 1) {
                k = 0;
                j++;
                radios[j] = new Array();
            }
            
            radios[j][k] = rds[i];
            k++;
        }
    }
    
    for(i = 0; i < radios.length; i++) {
        if(radios[i][0].checked =='' && radios[i][1].checked =='') {
            str += radios[i][0].name +',';        
        }
    }
    
    
    if(str !='') {
        alert("Nie zaznaczono:"+str);
        return false;
    } else {
        return true;
    }
}
</script>

[HTML] pobierz, plaintext 
<form action="" method="post" onsubmit="return check()">
    tak: <input type="radio" name="radio1" value="tak" />
    nie: <input type="radio" name="radio1" value="nie" />
    <br /><br />
    tak: <input type="radio" name="radio2" value="tak" />
    nie: <input type="radio" name="radio2" value="nie" />
    <br /><br />
    <input type="submit" name="submit" value="go" />
</form>
[HTML] pobierz, plaintext