Working Browser for In-Game PC.

Hi there, I've been working on a game for awhile now, and for some reason this seems to stump me the most. So, what I'm planning to do is try and make a working browser on the game. Another thing is to adding, I'm working on Unity 5, and already have a browser set up. Here's an image.\

So, another thing to know to adding, I'm trying to add where if the player just types in a random link, it'll just give them an error like "This page cannot be accessed at this time. Please try again later." Which I can do that, but I don't know how to exactly how to script using the Input Field. So if they typed a wrong URL, (Ex: www.blahblah.saq) the script will then open a UI Image. Like, seriously. If anyone can help with this, it would be life saving. Thank you! :D