//取得 checkbox中 所有被選取的選項值
function getCheckedValue()
{
    var checkbox = document.forms[0].elements['checkbox2'];
    if( checkbox != null ){
        if (!checkbox.length && checkbox.type.toLowerCase() == 'checkbox')
        {
            return (checkbox.checked)?checkbox.value:'';
        }
       
        if (checkbox[0].tagName.toLowerCase() != 'input' || checkbox[0].type.toLowerCase() != 'checkbox')
        {
            return '';
        }

        var val = [];
        var len = checkbox.length;
        for(i=0; i        {
            if (checkbox[i].checked)
            {
                val[val.length] = checkbox[i].value;
            }
        }
        return (val.length)?val:'';
    }else
        return false;
}