如何实现OC与JS的交互

#import <JavaScriptCore/JavaScriptCore.h>

- (void) webViewDidFinishLoad:(UIWebView *)webView{
    JSContext *context = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
    context[@"favQues"] = ^{
        NSArray *a = [JSContext currentArguments];
        for (id obj in a) {
            NSLog(@"obj:%@",obj);
        }
    };
}

function QMAction(id, subject, el) {
    favQues(id,subject,el);
}

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
    NSString *requestUrlStr = [[request.URL absoluteString] stringByRemovingPercentEncoding];
    if ([requestUrlStr hasPrefix:@"objc://"]) {
        NSArray *a = [requestUrlStr componentsSeparatedByString:@"://"];
        NSString *paramStr = a[1];
        NSArray *a1 = [paramStr componentsSeparatedByString:@":/"];
        if (a1.count > 0) {
            NSLog(@"%@-%@",a1[1],a1[2]);
        }else{
            NSLog(@"没有参数");
        }
        return NO;
    }
    return YES;
}

function QMAction(at, id, subject, el) {
    window.location.href="objc://"+":/"+subject+":/"+id;
}