Get the full height of WebView content using Javascript


I'm using a UIWebView for displaying content, in the form of an HTML string – not a website, higher than the screen of the iPhone, without needing to scroll in the webView itself, leaving that to the parent scrollView.

To achieve this, I need a way to get the total document size, including the scrollable area, to set the webView's height. I have tried a number of different Javascript solutions:

(document.height !== undefined) ? document.height : document.body.offsetHeight // Returns height of UIWebView
document.body.offsetHeight // Returns zero
document.body.clientHeight // Returns zero
document.documentElement.clientHeight // Returns height of UIWebView
window.innerHeight // Returns height of UIWebView -2
document.body.scrollHeight // Returns zero

Is there a solution that actually works?

Current (nonworking) code:

[[[self.singlePost.contentText subviews] lastObject] setScrollEnabled:NO];
int content_height = [[self.singlePost.contentText stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] intValue];
NSLog(@"Content_height: %d", content_height);
CGRect rect = self.singlePost.contentText.frame;
rect.size.height = content_height;
self.singlePost.contentText.frame = rect;

There is no need to use Javascript in iOS 5.0 and up - you have direct, documented access to its scrollView:

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    CGFloat contentHeight = webView.scrollView.contentSize.height;
    // ....

To get the total height of the contents of the webView.