MySQL: Large VARCHAR vs. TEXT?

I’ve got a messages table in MySQL which records messages between users. Apart from the typical ids and message types (all integer types) I need to save the actual message text as either VARCHAR or TEXT. I’m setting a front-end limit of 3000 characters which means the messages would never be inserted into the db as longer than this.

How to open URL that is inside of textbox

So I have tried this one:
<input type="url" id="textbox" /> <input type="button" id="btn" value="Submit" onClick="javascript: window.location = document.getElementById('textbox').value; />
What I tried to do was that my site would have a text area where I can write a URL and then once you’ve pressed “Submit” would go to that site without opening a new window or tab. What mistake I have made?