title: UIWebView load error
body: <p>When I load some webpages in ios using <code>UIWebView</code>, sometimes it shows nothing ,and throw errors like following</p>
  
  <pre><code>WebKit discarded an uncaught exception in the webView:decidePolicyForNavigationAction:request:frame:decisionListener: delegate: &lt;NSRangeException&gt; *** -[__NSCFString substringToIndex:]: Range or index out of bounds
  </code></pre>
  
  <p>and I dont know why, who could point me out? thanks</p>