location.href不跳转是怎么回事

function login(type, referer)
{   
    var username = $("#username_login").val();
    var password = $("#password_login").val();
    var keep = $("#keep_login").attr("checked") == 'checked' ? 1 : 0;
    
    if (username == '') 
    {
        $("#username_login").focus();
        return false;
    }
    if (password == '') 
    {
        $("#password_login").focus();
        return false;
    }    $("#submit_login").val('登录中...').attr('disabled', true);
    
    $.post(SITE_URL+'member/login/dologin?rand=' + Math.random(), {"username":username,"password":md5(password),"keep":keep}, function(response) 
    {   
        if (response.error_code) 
        {
            if (type == 1)
            {
                show_alert(response.msg+'('+response.error_code+')');
            }
            else
            {
                $('#show_info').html(response.msg+'('+response.error_code+')');
            }
            
            $("#submit_login").val('登 录').attr('disabled', false);
        } 
        else 
        {   
            if (type == 1)
            {   
                if (referer)
                {
                    location.href = referer;
                }
                else
                {   location.href = SITE_URL+"member/follow";
                    if (response.data.is_complete_profile)
                    {   
                        if (response.data.is_upload_avatar)
                        {   
                            //alert(SITE_URL+"member/follow");return false;
                            location.href = SITE_URL+"member/follow";                        }
                        else
                        {
                            location.href = SITE_URL+"member/profile/avatar";
                        }
                    }
                }
            }
            else
            {   
                if (referer)
                {
                    location.href = referer;
                }
                else
                {
                    location.reload(); 
                }
            }
        }
    }, "json");
}这是一个登陆函数，执行到红色字体那，alert有结果，也是正确的，但是location.href却不跳转是怎么回事？？？
跳转地址是正确的。