这种代码怎么做？

<script>
mydate = new Date();    
myyear = mydate.getYear();    
w=new Array("星期日","星期1","星期2","星期3","星期4","星期5","星期6")
ShowLifeNav()
function ShowLifeNav(){
if(myyear < 300)myyear = 1900 + myyear ;    
mymonth = mydate.getMonth()+1;    
today = mydate.getDate(); 
if(today<10) today="0"+today
if(mymonth<10) mymonth="0"+mymonth
myhour = mydate.getHours();    
if(myhour<6)       welcomestring="凌晨好";    
else if(myhour<9)      welcomestring="早上好";    
else if(myhour<12)      welcomestring="上午好";    
else if(myhour<14)      welcomestring="中午好";    
else if(myhour<17)      welcomestring="下午好";    
else if(myhour<19)      welcomestring="傍晚好";    
else if(myhour<22)      welcomestring="晚上好";    
else
welcomestring="夜里好";
document.write("<font color=#808080>欢迎您！"+myyear+"年"+mymonth+"月"+today+"日" + w[mydate.getDay()]+welcomestring+"</font>");
}
</script>