Interact more seamlessly with the content in a UIWebView

UIWebView+PlatformIntegration.m

#import "UIWebView+PlatformIntegration.h"

@implementation UIWebView (PlatformIntegration)

- (NSString*)pi:(NSString*)function {
    return [self stringByEvaluatingJavaScriptFromString:
                    [NSString stringWithFormat:@"PlatformIntegration.%@", function]];
}

- (BOOL)platformIntegrationEnabled {
    return ![@"undefined" isEqualToString:[self stringByEvaluatingJavaScriptFromString:@"typeof(PlatformIntegration)"]];
}

- (void)submitForm {
    [self pi:@"submitForm();"];
}

- (void)submitFormWithSelector:(NSString*)selector {
    [self pi:[NSString stringWithFormat:@"submitForm('%@');", selector]];
}

- (void)setValue:(NSString*)value forFormField:(NSString*)fieldID {
    [self pi:[NSString stringWithFormat:@"setFormValue('%@', '%@');", fieldID, value]];
}

- (void)observe {
    if ([self platformIntegrationEnabled]) {
        [self pi:@"observe();"];
    }
}

- (BOOL)handlePlatformIntegrationEventsForRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType delegate:(id<PlatformIntegrationDelegate>)delegate {
    NSString *uri = request.URL.absoluteString;
    NSArray *components = [uri componentsSeparatedByString:@":"];
    if ([@"platformintegration" isEqualToString:[components objectAtIndex:0]]) {
        if ([@"formchanged" isEqualToString:[components objectAtIndex:1]]) {
            if ([delegate respondsToSelector:@selector(webViewFormChanged:)])
                [delegate webViewFormChanged:self];
        }
        return NO;
    }
    else {
        if ([delegate respondsToSelector:@selector(webView:loadedNewURL:)]) {
            [delegate webView:self loadedNewURL:request.URL];
        }
        return YES;
    }
}

@end