// JScript 文件
function check()
    {
        if(document.getElementById("tbUserCode").value==""||document.getElementById("tbUserPwd").value=="")
        {
            alert("用户名或密码不能为空!");
            return false;
        }
        var allcookies = document.cookie;
        var cookie_pos = allcookies.indexOf("CheckCode");
        if (cookie_pos != -1)
        {
            // 把cookie_pos放在值的开始，只要给值加1即可。
            cookie_pos += "CheckCode".length + 1;
            var cookie_end = allcookies.indexOf(";", cookie_pos);
            if (cookie_end == -1)
            {
                cookie_end = allcookies.length;
            }
            var value = unescape(allcookies.substring(cookie_pos, cookie_end));
            if(value.toLowerCase() != document.getElementById("txtCode").value.toLowerCase())
            {
                alert("验证码不正确!");
                ChangeCheckCode();
                document.getElementById('txtCode').value="";
                document.getElementById('txtCode').focus();
                return false;
            }
        }
        else
        {
            alert("请误禁用cookie!");
            return false;
        }
        
        return true;
    }
    
function   ChangeEnterToTab(event)
{ 
    if(document.all) if(event.keyCode==13) event.keyCode=9;
}

//单击图片修改验证码
function ChangeCheckCode()
{
    var checkFrame = document.getElementById('CheckImg');
    checkFrame.src = "Default.aspx?math="+ Math.random();
}
function focusInput(){
    if(document.getElementById('tbUserCode').value == "") document.getElementById('tbUserCode').focus();
}