javascript adding a day month date year to html from js file?

[Thomas D]

i have this now

<script>
var d = new Date();
var weekday= new
array("Sunday","Monday","Tuesday"...)
var monthName= new
array ("Jan","Feb","Mar",...)
document.write(weekDay [d.getDay()] + " ")
document.write(d.getDate() + " ")
document.write(monthName[d.getMonth()]+ " ")
document.write(d.getFullYear())
</script>

how can i reference this in my html header???????????????????