Webview: block JavaScript popups

WebView: Block JavaScript Popups

WebViews are powerful tools for integrating web content within native applications. However, they also inherit the security vulnerabilities of web browsers, including the potential for malicious JavaScript code to launch popups.

This article will explore how to block JavaScript popups within a WebView, enhancing user experience and security.

Methods for Blocking JavaScript Popups

1. WebView Settings

Many WebView frameworks provide built-in settings to control JavaScript behavior. These settings offer a straightforward approach to block popups.

Android WebView

WebView webView = findViewById(R.id.webView);
WebSettings settings = webView.getSettings();
settings.setJavaScriptEnabled(true); // Enable JavaScript if needed
settings.setJavaScriptCanOpenWindowsAutomatically(false); // Disable automatic popup opening

iOS WKWebView

WKWebViewConfiguration *configuration = [WKWebViewConfiguration new];
configuration.preferences = [WKPreferences new];
configuration.preferences.javaScriptCanOpenWindowsAutomatically = NO;
WKWebView *webView = [[WKWebView alloc] initWithFrame:CGRectZero configuration:configuration];

2. JavaScript Injection

By injecting JavaScript code into the WebView, you can intercept and block popup attempts.

JavaScript Code

window.open = function(url, target, features) {
  // Prevent popups from opening
  return false;
};

This code overwrites the default window.open function, preventing popups from being opened.

Injecting JavaScript

To inject this code, use the following methods:

• Android WebView: Use the addJavascriptInterface method.
• iOS WKWebView: Use the evaluateJavaScript method.

3. Content Filtering

By filtering the HTML content loaded in the WebView, you can remove elements that trigger popups.

Example

// Assuming HTML content is stored in the 'html' variable
html = html.replace(/]*>(.*?)<\/script>/gi, ''); // Remove JavaScript tags
html = html.replace(/]*target="_blank"[^>]*>/gi, ''); // Remove target="_blank" attribute