webview 支持alert

final WebView browser = (WebView)findViewById(R.id.browser);
/* JavaScript must be enabled if you want it to work, obviously */
browser.getSettings().setJavaScriptEnabled(true);

final Context myApp = this;

/* WebChromeClient must be set BEFORE calling loadUrl! */
browser.setWebChromeClient(new WebChromeClient() {
    @Override
    public boolean onJsAlert(WebView view, String url, String message, final android.webkit.JsResult result)
    {
        new AlertDialog.Builder(myApp)
            .setTitle("javaScript dialog")
            .setMessage(message)
            .setPositiveButton(android.R.string.ok,
                    new AlertDialog.OnClickListener()
                    {
                        public void onClick(DialogInterface dialog, int which)
                        {
                            result.confirm();
                        }
                    })
            .setCancelable(false)
            .create()
            .show();

        return true;
    };
});

/* load a web page which uses the alert() function */
browser.loadUrl("http://lexandera.com/files/jsexamples/alert.html");