Contacts Application Hijacking my WebPage

I have Lenovo K1 tablet, which is preloaded with Browser and Contacts apps. I have a website with a webpage containing a Sudoku puzzle grid. Often the grid shows possible Sudoku answers for a cell as a string of numbers, like 2346789. The web app allows user to touch on the number string to hide it. When the string is touched a JavaScript routine is called which hides the string, and returns False to tell the browser that nothing has happened.

However, it seems that when number strings look to the Browser like a phone number, the Contacts app hijacks the page and asks if I want to save this goofy "phone number" with a Contact. I've tried various things to keep the Contacts app out of my hair, including "Force Close" under Manage Apps, but it keeps bouncing back.

This doesn't happen every time -- it seems to be sensitive to specific number sequences. And often what it proposes as a phone number is a combination of strings appearing in adjacent Sudoku cells.

It appears that Contacts is tightly integrated with the installed Android Browser. Any suggestions for dealing with this problem would be greatly appreciated.