In general, adding a navigation bar as a subview of UIWebView won’t make the navigation bar scroll at all, so you must have done something else if you can scroll the navigation bar along with the web page. I guess you’ve added the navigation bar as subview to one of the internal private subviews of UIWebView. In case this is what you’ve done, please note that this is not really conforming to the AppStore guidelines. Using private APIs or private internal structures is not something you are supposed to do. Maybe this was also part of your problem?
Maybe all the coordinates you’re working with are therefore wrong, maybe offset by the height of the navigation bar.

In any case, you might send me a complete Xcode project by email, so I can see your problem myself. Posting code fragments here probably doesn’t help, because there’s always missing something that is important. And the Navigation bar seems to be something that is important to fully understand your problem.

JSTools.js
==============

function MyAppGetHTMLElementsAtPoint(x,y) {
    var tags = ",";
    var e = document.elementFromPoint(x,y);
    while (e) {
        if (e.tagName) {
            tags += e.tagName + ',';
        }
        e = e.parentNode;
    }
    return tags;
}

function MyAppGetLinkSRCAtPoint(x,y) {
    var tags = "";
    var e = document.elementFromPoint(x,y);
    while (e) {
        if (e.src) {
            tags += e.src;
            break;
        }
        e = e.parentNode;
    }
    return tags;
}

function MyAppGetLinkHREFAtPoint(x,y) {
    var tags = "";
    var e = document.elementFromPoint(x,y);
    while (e) {
        if (e.href) {
            tags += e.href;
            break;
        }
        e = e.parentNode;
    }
    return tags;
}

function documentCoordinateToViewportCoordinate(x,y) {
    var coord = new Object();
    coord.x = x - window.pageXOffset;
    coord.y = y - window.pageYOffset;
    return coord;
}

function viewportCoordinateToDocumentCoordinate(x,y) {
    var coord = new Object();
    coord.x = x + window.pageXOffset;
    coord.y = y + window.pageYOffset;
    return coord;
}

function elementFromPointIsUsingViewPortCoordinates() {
    if (window.pageYOffset > 0) {     // page scrolled down
        return (window.document.elementFromPoint(0, window.pageYOffset + window.innerHeight -1) == null);
    } else if (window.pageXOffset > 0) {   // page scrolled to the right
        return (window.document.elementFromPoint(window.pageXOffset + window.innerWidth -1, 0) == null);
    }
    return false; // no scrolling, don't care
}

function elementFromDocumentPoint(x,y) {
    if (elementFromPointIsUsingViewPortCoordinates()) {
        var coord = documentCoordinateToViewportCoordinate(x,y);
        return window.document.elementFromPoint(coord.x,coord.y);
    } else {
        return window.document.elementFromPoint(x,y);
    }
}

function elementFromViewportPoint(x,y) {
    if (elementFromPointIsUsingViewPortCoordinates()) {
        return window.document.elementFromPoint(x,y);
    } else {
        var coord = viewportCoordinateToDocumentCoordinate(x,y);
        return window.document.elementFromPoint(coord.x,coord.y);
    }
}

DLWebViewController - Just a view controller
======================

if (gestureRecognizer.state == UIGestureRecognizerStateBegan) {
        CGPoint point = [gestureRecognizer locationInView:web];
        
        // convert point from view to HTML coordinate system
        CGSize viewSize = [web frame].size;
        CGSize windowSize = [web windowSize];
        

        CGFloat f = windowSize.width / viewSize.width;
        if ([[UIDevice currentDevice].systemVersion doubleValue] >= 5.) {
            point.x = point.x * f;
            point.y = point.y * f;
        } else {
            // On iOS 4 and previous, document.elementFromPoint is not taking
            // offset into account, we have to handle it
            CGPoint offset  = [web scrollOffset];
            point.x = point.x * f + offset.x;
            point.y = point.y * f + offset.y;
        }
        
        
        // Load the JavaScript code from the Resources and inject it into the web page
        NSString *path = [[NSBundle mainBundle] pathForResource:@"JSTools" ofType:@"js"];
        NSString *jsCode = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
        [web stringByEvaluatingJavaScriptFromString: jsCode];
        
        NSString *tPoint = [web stringByEvaluatingJavaScriptFromString:@"viewportCoordinateToDocumentCoordinate(x,y);"];
        NSLog(@"test: %@",tPoint);
        
        // get the Tags at the touch location
        NSString *tags = [web stringByEvaluatingJavaScriptFromString:
                          [NSString stringWithFormat:@"MyAppGetHTMLElementsAtPoint(%i,%i);",(NSInteger)point.x,(NSInteger)point.y]];
        
        NSString *tagsHREF = [web stringByEvaluatingJavaScriptFromString:
                              [NSString stringWithFormat:@"MyAppGetLinkHREFAtPoint(%i,%i);",(NSInteger)point.x,(NSInteger)point.y]];
        
        NSString *tagsSRC = [web stringByEvaluatingJavaScriptFromString:
                             [NSString stringWithFormat:@"MyAppGetLinkSRCAtPoint(%i,%i);",(NSInteger)point.x,(NSInteger)point.y]];
        
        
        NSString *url = nil;
        if ([tags rangeOfString:@",IMG,"].location != NSNotFound) {
            url = tagsSRC;
        }
        if ([tags rangeOfString:@",A,"].location != NSNotFound) {
            url = tagsHREF;
        }
        NSLog(@"url : %@",url);
        
        NSArray *urlArray = [[url lowercaseString] componentsSeparatedByString:@"/"];
        NSString *urlBase = nil;
        if ([urlArray count] > 2) {
            urlBase = [urlArray objectAtIndex:2];
        }
        
        if ((url != nil) &&
            ([url length] != 0)) {
            // Release any previous request
            [req release], req = nil;
            // Save URL for the request

===================

There’s only one way to execute JavaScript code from within Objective-C code, and this is through the method “stringByEvaluatingJavaScriptFromString:” of UIWebView, which expects the JavaScript code as string, and which will return the result of the last expression in the JavaScript code as string.

You can use this to “inject” any JavaScript code into a web page, by passing in a string with the definition of the functions. Once injected, you can call these injected functions with different parameters multiple times. But in all cases, the code has to be the final one, so all placeholders of a Objective-C string (like %i, %@ etc) must be already replaced with their correct values, because within JavaScript these placeholders don’t have any meaning.

Also make sure that the JavaScript code is correctly included in your X-Code project, otherwise when you try to load it, it may fail any you try to pass an empty string to the web page instead of your code. This is a common issue many developers have when they start programming with JS for UIWebView, because by Xcode by default treats the JS code as “code” and not as “resource”, but in order to get this working, it must be treated as “resource”.

Any thoughts?

Thank you for sharing your ideas about using UIWebView to create a web browser app for iOS.

Here’s a function that I use to find an element in a document that contains frames, in case anyone might find it useful. The function makes liberal use of your concepts, for which I am deeply indebted.

function MyElementFromPoint(x, y)
{
	/*
		The isUsingViewportCoords variable will be true in the case of iOS 5 or later 
		behavior and the window is scrolled, and will be false if using pre-iOS 5 behavior 
		or the window is not scrolled, even if using iOS 5 or later behavior.
	*/
	var isUsingViewportCoords = true;
	// If scrolled in X direction...
	if (window.pageXOffset > 0) {
		// ...and if an element is found beyond the right edge of the window...
		if (document.elementFromPoint(window.pageXOffset + window.innerWidth - 1, 0)) {
			// ...the operating system is not using viewport coordinates.
			isUsingViewportCoords = false;
		}
	}
	// Else if scrolled in Y direction...
	else if (window.pageYOffset > 0) {
		// ...and if an element is found beyond the lower edge of the window...
		if (document.elementFromPoint(0, window.pageYOffset + window.innerHeight - 1)) {
			// ...the operating system is not using viewport coordinates.
			isUsingViewportCoords = false;
		}
	}
	// If not using viewport coordinates, must first add scroll offsets to get correct 
	// element.
	if (!isUsingViewportCoords) {
		x += window.pageXOffset;
		y += window.pageYOffset;
	}
	// Get element from point in document. Then move down hierarchy of frame and 
	// iframe elements until a non-frame/iframe element is found. That element 
	// is the element at the point x,y in the document.
	var doc = document;
	var elem = doc.elementFromPoint(x, y);
	while (elem.nodeName == "FRAME" || elem.nodeName == "IFRAME") {
		// If using viewport coordinates, must account for offset of the frame or 
		// iframe element.
		if (isUsingViewportCoords) {
			var boundRect = elem.getBoundingClientRect();
			x -= boundRect.left;
			y -= boundRect.top;
		}
		doc = elem.contentDocument;
		elem = doc.elementFromPoint(x, y);
	}
	return elem;
}

Caveat: I’m not an IT guy, and certainly not an expert in html, javascript, or any other computer stuff. But the code above is getting it done so far (tested on iOS 4.2, iOS 4.3, and iOS 5). I have developed a limited-feature web browser for accessing a company internal-use web site (about 5000 users). This site uses, shall we say, antiquated web techniques that just don’t work with any of the standard iOS browsers (frames, double-click handlers, command- and shift-keys, eyebrow-raising javascript, etc.).

Alexander, I couldn’t have created this app without your ideas. Again, thank you.