I would like to use a placeholder for a message saying "Last update on [Date]". I found some code on the internet but I would like to adjust the font, size and color. I was only able to adjust the color. The font continues to be Arial and the size retains its default size. Any ideas what's wrong in the code?

Code:
<SCRIPT LANGUAGE="JavaScript">
function Initialize()
{ this.length = Initialize.arguments.length
for ( var i = 0; i < this.length; i++ ) this[ i + 1 ] =
Initialize.arguments[ i ]
}

var DayOfWeek = new Initialize("Last update", "Last update", "Last update", "Last update", "Last update", "Last update", "Last update" );
var MonthName = new Initialize("Jan.", "Feb.", "Mar.", "April",
"May", "June", "July", "Aug.", "Sep.", "Oct.", "Nov.",
"Dec.");
var LastModifiedDate = new Date(document.lastModified);

document.write(DayOfWeek[(LastModifiedDate.getDay() + 1 )] ,": ");
document.write( LastModifiedDate.getDate() ," "  );
year=LastModifiedDate.getYear();
if (year<100) year+=100;
if (year<1000) year+=1900;document.write(MonthName[(LastModifiedDate.getMonth() + 1)] ," ",( year ) );
</SCRIPT>

<div style="font:open-sans;font-size:18px;color:004c7e">
<!-- SCRIPT OUTPUT -->
</div>