OC代码

- (WKWebView *)webView
{
    if (!_webView) {
        WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];
        WKUserContentController * wkUController = [[WKUserContentController alloc] init];
        [wkUController addScriptMessageHandler:self name:@"jsCallOCFunction"];
        config.userContentController = wkUController;
        _webView = [[WKWebView alloc] initWithFrame:CGRectMake(0, 0, kScreenWidth, kScreenHeight - kNavHeight - kTabbarHeight)configuration:config];
        _webView.backgroundColor = [UIColor whiteColor];
        _webView.UIDelegate = self;
        _webView.scrollView.bounces = NO;
        _webView.navigationDelegate = self;
    }
    return _webView;
}

实现代理:这里以点击H5文件链接下载文件为例

#pragma mark - WKScriptMessageHandler
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message {
    NSDictionary *dic = message.body;
    if ([dic[@"method"] isEqualToString:@"downloadFilePreview"]) {
        NSString *url = dic[@"url"];
        NSMutableDictionary *params = [NSMutableDictionary dictionary];
        params[@"name"] = dic[@"name"];
        [MBProgressHUD showHUDAddedTo:self.view animated:YES];
        [HttpTool downLoadFileWithUrl:url params:params success:^(id json) {
            [MBProgressHUD hideHUDForView:self.view];
            if (json) {
                DownLoadFilePreviewController *downVc = [[DownLoadFilePreviewController alloc]init];
                downVc.url = json;
                self.isrefresh = NO;
                [self.navigationController pushViewController:downVc animated:YES];
            }else{
                [MBProgressHUD hideHUDForView:self.view];
                [MBProgressHUD showError:@"下载文件失败，请稍后重试"];
            }
        } failure:^(NSError *error) {
            [MBProgressHUD hideHUDForView:self.view];
            [MBProgressHUD showError:@"下载文件失败，请稍后重试"];
        }];
    }
}

H5代码

window.webkit.messageHandlers.scan.postMessage()