Js獲取批量選擇CheckBox的值

<script>
function GetBatchCheckBoxValue(){
    //判斷至少選擇一條數據
    var chks = document.getElementsByTagName('input');
    var bl = true;
    for (var i = 0; i < chks.length; i++) {
        if (chks[i].checked) {
            bl = false;
            break;
        }
    }
    if (bl) {
        alert('至少選擇一條信息');
        return
    }

    //獲取CheckBox的值
    var str = "";    
    var chk = document.getElementsByName("selected");    
    for (var i = 0; i < chk.length; i++) {        
        if (chk[i].checked) {            
            str += chk[i].value + ","; //獲得用逗號分割的字符串        
            }    
    }    
    alert(str); //返回一個拼接成的字符串，用逗號分隔開(例：381,380,377,376,372,371,370,368,367,362,)}
</script>