Can I automatically make a phone call without pressing a button?

I would like to visit my web page and have the page immediately dial a phone number WITHOUT the user pressing additional buttons.

I'm trying to do this by placing the following code in the Header of my web page:

<a href="tel:+1234567890">Test</a>

However, this is only opening the web page. It's not dialing anything. If I place this same code on a button, it will dial when I press the button. Any ideas? Thank you =)