Add the configuration shown below in the in web.config file. This configuration setup enable gzip compression on static and on dynamic content.
<system.webServer><httpCompressiondirectory="%SystemDrive%\inetpub\ temp\IIS Temporary Compressed Files"><schemename="gzip"dll="%Windir%\system32\inetsrv\gzip.dll"/><dynamicTypes><addmimeType="text/*"enabled="true"/><addmimeType="message/*"enabled="true"/><addmimeType="application/javascript"enabled="true"/><addmimeType="*/*"enabled="false"/></dynamicTypes><staticTypes><addmimeType="text/*"enabled="true"/><addmimeType="message/*"enabled="true"/><addmimeType="application/javascript"enabled="true"/><addmimeType="*/*"enabled="false"/></staticTypes></httpCompression><urlCompressiondoStaticCompression="true"doDynamicCompression="true"/></system.webServer>