UIWebViewでリンククリックで処理

読み込むhtml
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<a href="js-call://camera">camera</a><br/><br/>
<a href="js-call://album">album</a><br/><br/>
<a href="js-call://alert">alert</a><br/><br/>
</body>
</html>

-(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
    NSLog(@"shouldStartLoadWithRequest");
    NSString *requestString = [[request URL] absoluteString];
    NSString *protocol = @"js-call://";
    if ([requestString hasPrefix:protocol]) {
        NSString *requestContent = [requestString substringFromIndex:[protocol length]];
        NSArray *vals = [requestContent componentsSeparatedByString:@"/"];
        if ([vals[0] isEqualToString:@"camera"]){
            [self startCamera];//カメラ起動
        }else if ([vals[0] isEqualToString:@"album"]){
            [self startAlbum];//カメラロール起動
        }else {
            [webView stringByEvaluatingJavaScriptFromString:@"alert('Not defined');"];//jsのalert実行
        }
        return NO;
    }
    return YES;
}