当dismissViewController时，WebViewJavascriptBridge不再调用

Question

当视图第一次显示时，js事件运行正常。比我使用presentViewController来显示我点击的图像。在dismissViewController之后，返回到webView，再次单击该图像，但js callHandler未运行。这是我的代码。

// oc file code

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    if (_bridge) { return; }

    _bridge = [WebViewJavascriptBridge bridgeForWebView:self.webView];

    [_bridge registerHandler:@"jsImagesList" handler:^(id data, WVJBResponseCallback responseCallback) {
        self.imageList = data;
    }];

    [_bridge registerHandler:@"openImageOnIndex" handler:^(id data, WVJBResponseCallback responseCallback) {
        [self openImageOnIndex:data];// use MWPhotoBrowser to show the image
    }];
}

// js file code

function setupWebViewJavascriptBridge(callback) {
    // just copy from WebViewJavascriptBridge
}

setupWebViewJavascriptBridge(function(bridge) {

    var objs = document.getElementsByTagName("img");
    var images = [];
    for(var i=0;i<objs.length;i++) {
        images.push(objs[i].src);
        objs[i].setAttribute('data-index',i);
        objs[i].onclick = function(){

            // just for test, let me know I can click the img
            document.body.style.backgroundColor = '#'+Math.floor(Math.random()*0xFFFFFF).toString(16);

            var di = this.getAttribute('data-index');

            // ----------- question -----------
            // first time it run, but when dismissViewController, it not run
            bridge.callHandler('openImageOnIndex', {'i': di}, function(response) {})
        }
    }
    bridge.callHandler('jsImagesList', images, function(response) {})
})

我该如何修改它，非常感谢！