try this
-(IBAction) incresethegeight:(id)sender
{
[UIView animateWithDuration:2 delay:1.0
options:UIViewAnimationOptionBeginFromCurrentState
animations:^{ self.view.alpha = 1; }
completion:^(BOOL fin){[self addHeight ];}];
}
-(void) addHeight
{ float height = webview.frame.size.height;
CALayer* simple = [[CALayer alloc]init];
simple = webview.layer;
CATransform3D currentTransform = simple.transform;
CATransform3D scaled = CATransform3DScale(currentTransform, 1.5, 1.5, 1.5);
simple.transform = scaled;
[simple setNeedsDisplay];
// or
// [webview setFrame:CGRectMake(0.0f, 0.0f, 320, height +30)];
}