title: synchronously load html content in UIWebView
body: <p>im using a UIWebView to show html content in my app, the app contains two arrows to navigate between topics just like a RSS reader app, but when the user hits up or down arrow, the next topic doesn't show up until the data come back and the user still able to interact with the UI which is a bit confusing,</p>
  
  <p>My question: how to block the UI when user moves to the next/back topic ? in other words how to make loadHTMLString:baseURL: works as a synchronous calling ? thanks !</p>