https://code.msdn.microsoft.com/windowsdesktop/HTMLEmbedActiveX-fbab105b but it is probably pretty heavy.
There is a good, simple Youtube that shows a very simple method. Adjust your file names accordingly.
what software are you using to develop your website? There are a lot of plugins and extra tools out there that can do this for you, at a cost of course, and it would not take you long to learn it. You sound bright enough to give it a go.
I don't know your application or what it is worth in time, but give this website (Angelcam) a look. You might like it.
I've asked Hikvision to provide feedback and am waiting their reply.
David- Hikvision has a Web SDK. I suggest you contact your local Hikvision Sales Reprentatitive. They can provide the manual. If you feel you want the Web SDK, they can make it available to you. Please note we will support integrators who purchase thru our authorized sales channels but we cannot support end users on the Web SDK.
David- what is your region and who did you contact? Are you an integartor or end user?
Depending on camera model and firmware version, you can give this a shot. I don't have access to a Hikvision camera to try it out, but I found this from some searches...
You have to make the second camera stream to MJPG
jpg stream : http://IP/Streaming/channels/1/picture
mjpg : http://IP/Streaming/channels/2 or http://IP/Streaming/channels/2/preview
Be sure to put substream on lower resolution and frame rate
If you use the jpg, you can use a HTML refresh to update the image...
Try it in IE & Firefox.