Alternative for https://gist.github.com/834907

app.css

html>body.pphone { font-size:12px; width: 980px; }
html>body.lphone { font-size:18px; width: 1470px; }
html>body.ppad { font-size:12px; width: 768px; }
html>body.lpad { font-size:15.99999996px; width: 1024px; }

index.html

<meta name="viewport" content="width=VIEWPORTWIDTH,maximum-scale=4.5;" id="viewport">

LoadHtml.m

NSArray *parts = [htmlstring componentsSeparatedByString:@"VIEWPORTWIDTH"]
NSString *html = [parts componentsJoinedByString:((UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) ? @"768" : @"980")];

ViewController.m

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
    switch (toInterfaceOrientation) {
        case UIInterfaceOrientationPortraitUpsideDown:
        case UIInterfaceOrientationPortrait:
            if ((UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)) {
                [webview stringByEvaluatingJavaScriptFromString:@"document.body.className = 'ppad'"];
            } else {
                [webview stringByEvaluatingJavaScriptFromString:@"document.body.className = 'pphone'"];
            }
            break;
        default:
            if ((UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)) {
                [webview stringByEvaluatingJavaScriptFromString:@"document.body.className = 'lpad'"];
            } else {
                [webview stringByEvaluatingJavaScriptFromString:@"document.body.className = 'lphone'"];
            }
            break;
    }
}