change webView Font size with Setting Bundle ! [iPhone SDK]

i want change my UI开发者_开发百科WebView with Setting bundle . what is the property for webview font ?

i know my codes is wrong !

if([defaults boolForKey:@"large_font"]) 
    {
        myWeb.font = [ UIFont fontWithName:myGhazal size:32.0f];
    }
    else {

        myWeb.font = [ UIFont fontWithName:myGhazal size:18.0f];
    }

Reference a css style sheet in your HTML document or put the style information into the top of the HTML document itself.

I think, you cannot set font size by code.

Regards.