VMware has released a new Fling, this enables a HTML5 web client for there ESXi 5.5 update 3 (not released yet) and 6.0.
This is like the old style web interface tor the old ESX 2.x.
It is installed as e VIB, on the hosts, and do not require a reboot.
This would be vary nice for VMware vSphere Hypervisor (the Free version), but i does not work with this right now.
You can find it here: https://labs.vmware.com/flings/esxi-embedded-host-client
William Lam has a Blog on this also, with a workaround for upgraded hosts, you can see it here: http://www.virtuallyghetto.com/2015/08/new-html5-embedded-host-client-for-esxi.html