- [Voiceover] Lets improve we created in the last movie by adding a list of all time zones as options under our forms select tag. Specifically what I want to do is create a dynamic list of these options where right now I have a hard-coded one for America/New York. I want to have a list of all the time zones that available in PHP listed dynamically. So lets think back, how do we get a list of all the time zones that PHP has available? We actually did exactly that back in the beginning of chapter two. And if you open up the file tz_identifiers.php you'll see the code where we demonstrated it. We had timezone_identifiers_list and that's the PHP function that returns an array that lists out all those time zone identifiers. There is also the object oriented version DateTimeZone::listIdentifiers and you can use that as well. Lets grab that. I'll grab both of them so that we can see that they both work. And I'm just going to move back over here to this file and at the very top lets put some PHP tags. And there we go. We got our identifiers list now as an array. Alright, now our page knows about the list. It has an variable set to the array of all the identifiers. Now what we want to do is come down here and loop through that array in order to output all the options. In order to do a loop you might notice we did the same thing when we demonstrated here with this foreach statement. Lets copy that as well. Bring that over here and right below our option we'll create new PHP tags and I'll paste in that loop. Now our loop was a little bit different than before because our loop just output the zone with a tag after it. And we don't want that tag. Instead what we want is to output the same kind of thing that we got here for our static option. We just want to do it dynamically. So that means that we need to echo out the option tags. Lets just put an option tag here at the beginning and lets put an option tag down here to close it up. Okay, so now our option tag needs a value. So I'm going to put a value in there. I'm going to do that with double quotes and I need to escape those double quotes because they are inside double quotes. Notice how I'm doing that. And the reason why I want to use these double quotes is because I'm going to use PHP's interpolation that allows me to put curly braces and then the variable name in there. Zone. So nice and simple like that. It's going to drop in the zone value for the value and then it's going to repeat the zone value down here for what the user sees as well. And that will give me the same thing I've got here on these three lines. I'm going to take out America/NewYork now because I'm going to get that in my full list of all these time zones. Alright so let's go back over here I'll close this file. We don't need that anymore. Let's go into Firefox and let's just reload our page. There you go. Preferred Time Zone. You'll see the select option got a little wider. It's because it has to accommodate all of these different options. You can see we have them all listed out here. You scroll up to the top. Everything from Africa all the way down here to the bottom. Pacific and then finally UTC at the very bottom. Now you can come up with something more complex than this. More than just a simple list of all the time zones. You can have something where you pick Pacific or Atlantic or Europe or America first and then from that you got a subset of time zones like Midway and Norfolk and Tahiti and so on. There's no reason that wouldn't work. But I think there's a lot to said for just keeping it simple and just keeping these as the actual values that PHP has so that we don't have the chance of messing it up in the process. So now we have a dynamic list of all time zones and our users can select the time zone that matches their current location. And then they can submit it. Now it won't do anything once we submit it. We'll have to create that form processing later. But before we do that I want us to improve this select option slightly by including the actual time zone offset from UTC in what the user sees. Let's do that in the next movie.

• published: 12 Mar 2016
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