Using Less in Visual Studio 2013 Web Project

Here is a cheat sheet on "what to do" to start using LESS on Visual Studio 2013 web project.

1. Install "dotless" using Package Manager Console ("install-package dotless") or the Nuget Package Manager
2. Open Web.config, locate the "dotless" section, and change it as the following.
   The main thing is to add

   <validation validateIntegratedModeConfiguration="false"/>
   

   to the <system.webServer> node.
   

   <dotless minifyCss="false" cache="true" web="false" />
   <system.webServer>
       <validation validateIntegratedModeConfiguration="false"/>
       <handlers>
         <add name="dotless" path="*.less" verb="GET" type="dotless.Core.LessCssHttpHandler,dotless.Core" resourceType="File" preCondition="" />
       </handlers>
   </system.webServer>
   

3. If the main less file is "my.less", which imports all other less files, add the following comment at the top of each less file except the "my.less".

   /// <reference path="my.less" />