第一步：引入库文件

import <JavaScriptCore/JavaScriptCore.h>

第二步：实现UIWebView 代理

//网页加载完成

• (void)webViewDidFinishLoad:(UIWebView *)webView{
  //隐藏网络请求加载图标
  [UIApplication sharedApplication].networkActivityIndicatorVisible = false;
  //取得html内容
  NSLog(@"%@",[self.webView stringByEvaluatingJavaScriptFromString:@"document.title"]);
  if (_webView.scrollView.mj_header.state == MJRefreshStateRefreshing)
  {
  [_webView.scrollView.mj_header endRefreshing];
  }
  JSContext *context = [self.webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
  context[@"oneKeyShare"] = ^() {
  NSArray *args = [JSContext currentArguments];
  [self oneKeyShare];
  };
  }