I have just tried it using
JS. and it works:
for zoom:
[webView stringByEvaluatingJavaScriptFromString:@"document. body.style.zoom = 5.0;"];
for scroll:
int scroll=20; //Pixels to scroll
NSString* s=[[NSString alloc] initWithFormat:@"window.scrollTo(0, %i)",scroll];
[webView stringByEvaluatingJavaScriptFromString:s];
