Alert on button click and move user to open new tab

I created a button with a link that opens in a new tab. I also used JavaScript for reminders.

Currently this code works fine. But after clicking OK in the Alert, the user stays on the same page. But I want to move the user to the newly opened tab. is it possible?

My code is -

<form><input type="button" id="anchor1" style="cursor:pointer" value="Click Here" onClick="window.open(href='http://www.google.com')"></form> 

<script type="text/javascript">
  var anchor = document.getElementById('anchor1');
    // or anchor = getElementsByTagName('a') then do ('a')[0]

    anchor.addEventListener('click', doSomething, false);

    function doSomething() {
        alert('You Are About To Open New Tab');
    }
</script>

need help

Here is my JSFIDDLE