var year = new Date().getFullYear();
       var month = new Date().getMonth()+1;
       var day = new Date().getDay();
       var hour = new Date().getHours();
       var date = new Date().getDate();
       switch(day)
       {
            case 0:
                day="日";
                break;
            case 1:
                day="一";
                break;
            case 2:
                day="二";
                break;
            case 3:
                day="三";
                break;
            case 4:
                day="四";
                break;
            case 5:
                day="五";
                break;
            case 6:
                day="六";
                break;
       }
       var greetings = "";
       if(hour>=6 && hour <=12)
            greetings += "早上好";
        else if(hour >12 && hour <=19)
            greetings += "下午好";
       greetings += "<br>今天是" + year+ "年"+month+"月"+date+"日";
       greetings+="<br>星期"+day;
       document.write(greetings);

------解决方案--------------------
JScript code

＜script language="Javascript"＞ 
　　today=new Date(); 
　　function date(){ 
　　this.length=date.arguments.length 
　　for(var i=0;i＜this.length;i++) 
　　this[i+1]=date.arguments } 
　　var d=new date("星期日","星期一","星期二","星期三","星期四","星期五","星期六"); 
　　document.write( 
　　"＜font color=##000000 style='font-size:9pt;font-family: 宋体'＞ ", 
　　today.getYear(),"年",today.getMonth()+1,"月",today.getDate(),"日", 
　　d[today.getDay()+1],"＜/font＞" ); 
　　＜/script＞