Part1. Creating a simple login with php and html

I just decided to write this for people that are curious on programming and how the internet and computers are structured. Also for keen enthusiasts on computers. Comments would be really much appreciated.

—Login.html— First off we look at the form part of the html which looks like this:

<form action="data.php" method="post"> Username: <br /> <input name="username" type="text"> <br /> Password: <br /> <input name="pass" type="password"> <br /> <input type="submit" value="Login"> <br /> </form>

Now i shall go through what the form does part by part.

<form action="data.php" method="post">

The form action tells the html that the data from the form is going to get sent to the data.php for processing. The method tells the form what type of way to sent it. This could be either GET or POST, prefably use the POST because it is a lot safer to use in your scripts.

<input name="username" type="text"> <br />

Tells the input box for the username to save the data for that box with the name username which is what you need to grab later on in using the php. The type is text because you want to set the box so you can read your username after inputted.

<input name="pass" type="password"> <br />

Tells the second input box that the data inside the box when the form is submitted the data to process it shall be named pass. The type is set to password so that if anyone is around you while logging in or registering they will not be able to see the password because the characters you input will be replaced with a *.

<input type="submit" value="Login"> <br />

This is the piece of the login box that creates the submit box. You can see that the type of input for the form is registered at the start of it with the type set as submit. The value part sets the writing to display inside the submit box as 'Login'.

</form>

Not forgetting to close off the form.

—data.php—

I shall do the same as i done with the login.html writing the script and explaining the code piece by piece:

<?php $user = $_POST['username']; $pass = $_POST['pass']; if ($user == "Tiberius" && $pass = "1337p4ss"){ header ('Location:http://site.com/admin/'); }else{ print "<h1>Error Unauthorised login</h1>"; }; ?>

The <?php tells the server to start processing the php. $user = $_POST['username']; Recives the data that the html sent in the username part of the html form which you set with <input name="username" into the php variable called user. You can tell it's a variable because it has $ at the start of it.

$pass = $_POST['pass'];

Once again you get the value that was sent from the <input name="pass" part of the html form registered into the variable with the name pass.

if ($user == "Tiberius" && $pass = "1337p4ss"){

This part checks to see if the data in the variable user that was sent from the html is the same as the string tiberius and if the password sent from the html form is the same as the string 1337pass. As you saw at the start it says if so if the data is true execute the code inside the { }.

header ('Location:http://site.com/admin/')

The header function is a function included in php to redirect to another page or site. So in this case if the username is what it should be and the pass is what it should be redirect to the admin part of the site.

}else{

This part closes the if the condition is true part to if it is false execute whatever is inside the { }.

print "<h1>Error Unauthorised login</h1>"

So if the username and password is not as it should be print <h1>Error Unauthorised login</h1> to the screen.

?> As you can tell this tells the php that the code has finished and is ready to execute if no errors in the php. Although that does not mean that your code will not run because it could run but there could be as it's called a bug somwhere in your code. Don't kid yourself as you will come across bugs or errors in your code or you could leave out a ; (Please note the ; at the end of the lines in the php is telling the php that the command or function in the code has ended. Don't forget to leave your comments. ;)

This post seems to be more of an article rather than a forum post.

c4p_sl0ck wrote: This post seems to be more of an article rather than a forum post.

Yea, submit it as an article and see what comments you get

erm… you could just goto http://site.com/admin/ without logging in :p

Do we have an article about session variables? If not, you could write one on that to go with the login article. ;)

Well thanks to everyone that got back to me. Yes i think that in part 2 will be about securing it with sessions, then if all is successfull and i get lots of replies i will start with the mySQL and proventing some methods of mySQL injections. Also where do you think i should include recursive scripts with isset ?