calling xcode method from javascript function to and get returned value

You can do pretty much what you need in webView:shouldStartLoadWithRequest:navigationType.

1. If you return NO from it, then the web view will not load the current request; this will make your app free of doing whatever it needs:

2. you can then either load a different request in the same web view (say an HTML string that embeds the presentation resource),

3. or, you can send a message to some controller of yours to run a different workflow altogether (display a different kind of view or whatever).

EDIT:

elaborating more option 2:

1. say that you have a view controller which embed the UIWebView and also acts as delegate for it;

2. you could define a method in the view controller which gets and HTML string and loads it into the web view, like this:

   - (void)loadContentInWebView:(NSString*)content {
        [_webView loadHTMLString:content  baseURL:nil];
   }
   

3. now, in webView:shouldStartLoadWithRequest:navigationType, you could do something like this:

   - (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType {
           if ([[[request URL] absoluteString] isEqual:WHATEVER]) {
                [self loadContentInWebView:HERE_THE_HTML];
                return NO;
       }
       return YES;
   }
   

What you should define here is:

 ([[[request URL] absoluteString] isEqual:WHATEVER])

i.e., the logics to understand when the user touched some link that should make a presentation loaded;

and:

  [self loadContentInWebView:HERE_THE_HTML];

i.e., define in some way the HTML content that you want to use so to have the presentation displayed.

i got a work around..although it is not a good practice:

in model: This method gets called whenever a request comes for this webview even when the page loads in webview

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    // check the request, if it's ajax callback, just return NO; other wise YES;


//    NSURLRequest *request = [self request];
    NSURL *url = [request URL];

    NSString *file = [url lastPathComponent];
    if ([file isEqualToString:@"Presentation.html"] == YES) {
        return YES;
    }

    if ([file isEqualToString:@"ajaxcallback.htm"] == YES) {
        // that means the ajax call is done, so you can call this 
        NSString *result = [web stringByEvaluatingJavaScriptFromString:@"getResponse();"];

        // don't forget to stop loading this fake page
        return NO;
    }
}

and in javascript:

   function sendRequestToApp(){
        window.location="http://www.domain.com/ajaxcallback.htm";
    }

    function getResponse(src){
        alert("response");
        document.getElementById("sample").src=src;
    }