With ASP.NET 4 we are introducing a new code expression syntax (<%:  %>) that renders output like <%= %> blocks do – but which also automatically HTML encodes it before doing so.  This eliminates the need to explicitly HTML encode content like we did in the example above.  Instead, you can just write the more concise code below to accomplish the exact same thing:

We chose the <%: %> syntax so that it would be easy to quickly replace existing instances of <%= %> code blocks.  It also enables you to easily search your code-base for <%= %> elements to find and verify any cases where you are not using HTML encoding within your application to ensure that you have the correct behavior.