oc获取JavaScript对象

//网页里要有以下的JS对象（字典）
//        <script type="text/javascript">
//        var dataForWeixin={
//        appId:"",
//        MsgImg:"http://img.0579.com/upload/20140514/20140514140335744.jpg",
//        TLImg:"http://img.0579.com/upload/20140514/20140514140335744.jpg",
//        url:window.location.href,
//        title:"\u6D59\u6C5F\u91D1\u51EF\u5FB7\u5DE5\u8D38\u6709\u9650\u516C\u53F8--\u6C38\u5EB7114",
//        desc:"\u5BA4\u5185\u95E8 \u5B89\u5168\u95E8 \u975E\u6807\u95E8",
//        fakeid:"",
//        callback:function(
//                          //这里是分享成功后的回调功能
//                          ){}
//        };
//        </script>

//如果获取到JS对象dataForWeixin，则修改分享信息
   if ([[webView stringByEvaluatingJavaScriptFromString:@"dataForWeixin.MsgImg"] length] != 0) {
       vTitle=[webView stringByEvaluatingJavaScriptFromString:@"dataForWeixin.title"];
       vDesc=[webView stringByEvaluatingJavaScriptFromString:@"dataForWeixin.desc"];
       vPic=[UIImage imageWithData:[NSData dataWithContentsOfURL:
	[NSURL URLWithString: [webView stringByEvaluatingJavaScriptFromString:@"dataForWeixin.MsgImg"]]]];
   }