text size help (not HTML)

I have a really nice website maker, Site Spinner, and I am makigna very simple website. But when it displays the text of a variable it has a pre set size. Is there a way of changing size in java script?

I have tried too use

[size=10]

document.write(stuff here)

[/size (can't put last ] in)

but that didn't work.

document.write("<font size=4>" + stuffhere + "</font>");

Yes! Thank you so much!