Develop for the web, not for a browser! Here’s a good quick read about why having a single web browser for all operating systems and devices would not be a good thing:
The article also included this quote from Steve Jobs that I found kind of interesting:
“What’s the point of focusing on making the product even better when the only company you can take business from is yourself?”
Competing browsers are part of what drives innovation on the web. Developing for the ever-changing hardware and software landscape of the web is definitely a challenge. It is important to test websites thoroughly – you want your users to have a good experience regardless of the device and browser they are using.