[self.webView stringByEvaluatingJavaScriptFromString:@"alertMessage('弹窗')"];

function alertMessage(message) {

    alert(message);

}

<a href="client://addImg/headImg">点我调用OC方法</a>

#pragma mark UIWebViewDelegate 方法

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {

    // 可以直接拿到发送请求的网址

    NSString *urlStr = request.URL.absoluteString;

    if ([urlStr hasPrefix:@"client://"]) { // 判断请求是不是以 client:// 开头

        //获得去除请求头的 url 路径

        NSString *urlContent = [urlStr substringFromIndex:[@"client://" length]];

        //用 / 来拆分字符串

        NSArray *urls = [urlContent componentsSeparatedByString:@"/"];

        NSString *funName = [NSString stringWithFormat:@"%@:", urls[0]]; // 从url获取方法名,带参数的方法,加冒号

        SEL callFun = NSSelectorFromString(funName);

        //取消警告

        # pragma clang diagnostic push

        # pragma clang diagnostic ignored "-Warc-performSelector-leaks"

        [self performSelector:callFun withObject:urls[1]]; // 调用 OC 中的方法，并且传递参数

        return NO;

    }

    return YES;

}

#pragma mark 此方法通过网页调用

-(void)addImg:(NSString *) headImg {

    NSLog(@"通过网页调用OC方法:%@",headImg);

}

- (void)jsClick {

    [self.webView stringByEvaluatingJavaScriptFromString:@"var script = document.createElement('script');"

     "script.type = 'text/javascript';"

     "script.text = \"function myFunction() { "   //定义myFunction方法

     "var field = document.getElementsByName('word')[0];"

     "field.value='WWDC2014';"

     "document.forms[0].submit();"

     "}\";"

     "document.getElementsByTagName('head')[0].appendChild(script);"];  //添加到head标签中  

    [self.webView stringByEvaluatingJavaScriptFromString:@"myFunction();"];

}