效果如下：

PHP端程式碼：

    /**
     * 日曆
     * 
     * @param string month
     */
    public static function day_report($params = [])
    {
        $month = $params['month'];
        if (empty($month))
        {
            $month = date('Y-m');
        }

        $month_begin = strtotime($month . '-01');
        
 
$month_end =  strtotime("+1 months", $month_begin) - 24*3600;
        
        $dt_begin = $month_begin - (date('N', $month_begin)-1) * 24*3600;
        $dt_end = $month_end + (7 - date('N', $month_end)) * 24*3600;

        $today = strtotime(date('Y-m-d'));

        $list = [];
        $dt = $dt_begin;
        
 
while ($dt <= $dt_end)
        {
            $class = '';
            if ($dt < $month_begin || $dt > $month_end)
            {
                $class .= ' other';
            }
            if ($dt == $today)
            {
                $class .= ' today';
            }
            if ($dt
 
 > $today)
            {
                $class .= ' future';
            }

            $list[] = [
                'dt'  => date('Y-m-d', $dt),
                'day' => date('j', $dt),
                'class' => $class,
            ];
            
            $dt += 24*3600;
        }

        $list = array_chunk($list, 7);

        // 月份選擇
        $month_val = strtotime($month . '-01');
        $month_cur = date('Y年m月', $month_val);
        $month_pre = date('Y-m', strtotime("-1 months", $month_val));
        $month_next = '';
        if ($month != date('Y-m'))
        {
            $month_next = date('Y-m', strtotime("+1 months", $month_val));
        }

        $data = [
            'month' => $month,
            'list' => $list,
            'month_cur' => $month_cur,
            'month_pre' => $month_pre,
            'month_next' => $month_next,
        ];

        return self::_success($data);
    }

HTML端程式碼：

<h3 class="page-header"><i class="fa fa-calendar"></i> 工作日曆</h3>

<style>
    .h3-month
    {
        margin:10px 0;
    }
    .h3-month span
    {
        display:inline-block;
        border-radius: 5px;
        background-color: #eee;
        border:solid 1px #ddd;
        padding:0 10px;
        font-size:0.9;
    }

    #tbDayList{
        width:auto;
    }
    #tbDayList th{
        font-size:30px;
    }
    #tbDayList .td-day{
        width:100px;
        height:10px;
        line-height: 100px;
        padding:0;
        font-size:50px;
        font-family:Impact, Haettenschweiler, 'Arial Narrow Bold', sans-serif;
        color:#72B9F7;
    }
    #tbDayList .other{
        color:#999;
    }
    #tbDayList .future{
        color:#bbb;
    }
    #tbDayList .today{
        color:blue;
    }
</style>
    
<h3 class="h3-month">
    <a href="/index.php?_=work_log::day_report&month={ $month_pre }"><i class="fa fa-chevron-left"></i></a>
    <span>{ $month_cur }</span>
    { if $month_next != '' }
    <a href="/index.php?_=work_log::day_report&month={ $month_next }"><i class="fa fa-chevron-right"></i></a>
    { /if }
</h3>

<table id="tbDayList" class="tb">
    <thead>
        <th>週一</th>
        <th>週二</th>
        <th>週三</th>
        <th>週四</th>
        <th>週五</th>
        <th style="color:blue;">週六</th>
        <th style="color:blue;">週日</th>
    </thead>
    <tbody>
        { foreach $list as $week }
        <tr>
            { foreach $week as $r }
            <td class="td-day { $r.class }" data-dt="{ $r.dt }">{ $r.day }</td>
            { /foreach }
        </tr>
        { /foreach }
    </tbody>
</table>