Hidden field use tip and a question

I thought others might find this tip useful too. I just started using gravity forms to collect customer support requests and I often need to know the user's IP address and browser user agent string to help in troubleshooting. Those are easy enough to insert into a hidden field but I wanted to take it further to streamline some of the steps I usually take even more.

So instead of just inserting {ip} in a hidden field, I put this:
http://www.maxmind.com/app/locate_ip?ips={ip}

That creates a URL I can just click to use MaxMind's geo IP lookup. So besides just the IP I can get an approximate geographical location and usually some info about their ISP.

Here's the question part. I'd like to to the same thing with the user agent string and send it over to http://useragentstring.com, which does a nice breakdown of browser features. The problem is, if I do something like this:
http://useragentstring.com/index.php?Analyze={user_agent}

it doesn't work because there are spaces in the string. I'm assuming this could be done with a hook but I could use a pointer in the right direction. Thanks.

Okay, I found a way to make it work. I created my hidden field and set Gravity Forms to insert {user_agent} into that field. Then I added some code to my functions.php to rewrite that field:

add_action("gform_pre_submission", "pre_submission_handler");
function pre_submission_handler($form_meta){
	global $_POST;
	// form id 1 is our main contact form
	if($form_meta["id"] != '1'){
		return;
	}
	//http://useragentstring.com/index.php?uas={user_agent}
	$_POST["input_7"] = 'http://useragentstring.com/index.php?uas=' . urlencode($_POST["input_7"]);
}

I wasn't quite sure how to create a field on the fly or I may have just grabbed the user agent from PHP and built the field in the script instead.