title: JavaScriptCore framework availability on iOS
body: <p>I am using the JavaScriptCore framework that was <a href="https://developer.apple.com/library/ios/releasenotes/General/WhatsNewIniOS/Articles/iOS7.html#//apple_ref/doc/uid/TP40013162-SW17">introduced in iOS 7</a>. My app has an <em>iOS 6.0</em> deployment target. I am linking the app with JavaScriptCore.framework (which is by default in <em>required</em> mode). The new <a href="https://developer.apple.com/LIBRARY/IOS/releasenotes/General/iOS70APIDiffs/index.html">JavaScript Objective-C classes</a> (<code>JSContext</code>, <code>JSValue</code> etc.) are obviously not available when running on iOS 6 but I can still use the plain C API, i.e. <code>JSGlobalContextCreate()</code>, <code>JSObjectCallAsFunction()</code> etc.</p>
  
  <p>If I link the MultipeerConnectivity framework which was also introduced in iOS 7 and I run my app on iOS 6, I get an expected crash at startup:</p>
  
  <pre class="lang-none prettyprint-override"><code>dyld: Library not loaded: /System/Library/Frameworks/MultipeerConnectivity.framework/MultipeerConnectivity
    Referenced from: /var/mobile/Applications/5AB83411-CEFC-437D-88F8-6B80C36CCE9F/MyApp.app/MyApp
    Reason: image not found
  </code></pre>
  
  <p>Why is my app not crashing with the same dyld error when I link the JavaScriptCore framework?</p>