Second submit button not working in php - php

Question

I have been having problems with the second button not running like the first button. this is the code I have:
<p>
<form method="POST">
<input placeholder="Username" type="text" name="username"><br /><br />
<input placeholder="password" type="password" name="password"><br /><br />
<input value="Login" type="submit" name="log_In">
</form>
</p>
</div>
<?php
if(isset($_POST['log_In'])) {
#$f_name = $_POST['fname'];
#$s_name = $_POST['sname'];
#$stud_Id = $_POST['studId'];
#$uname = $_POST['uname'];
#$pass = $_POST['pass'];
#$rpass = $_POST['rpass'];
#$email = $_POST['email'];
#$remail = $_POST['remail'];
#var_dump($f_name);
header("Location:home.php");
}
?>
</div>
<div align="right">
<div>
<p>
<h2>Sign Up</h2>
</p>
<p>
<form>
<input placeholder="Forename" type="text" name="fname" id="Forename"><br /><br />
<input placeholder="Surname" type="text" name="sname"><br /><br />
<input placeholder="Student Id" type="text" name="studId"><br /><br />
<input placeholder="Username" type="text" name="uname"><br /><br />
<input placeholder="password" type="password" name="pass" min="6" max="32"><br /><br />
<input placeholder="Re-type password" type="password" name="rpass" min="6" max="32"><br /><br />
<input placeholder="Email" type="" name="email"><br /><br />
<input placeholder="Re-type Email" type="remail" name="remail"><br /><br />
<input value="Sign Up" type="submit" name="sign_Up">
</form>
</p>
</div>
<?php
if(isset($_POST['sign_Up'])) {
header("Location:home.php");
}
?>
</div>
"if(isset($_POST['sign_up'])) {" is not being run and is just refreshing the page and removing all items from the form.
thanks

Answer 1

By default <form> method is GET. So if(isset($_POST['sign_Up'])) won't work. Change it to if(isset($_GET['sign_Up'])).
Or change your second form tag to:
<form method="POST">
Remember not to use header function after generating HTML content, move it to top!
header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP.
So it will be better if it is like this:
<?php
if(isset($_POST['log_In']) || isset($_POST['sign_Up'])) {
header("Location:home.php");
}
?>
<form method="POST">
<input placeholder="Username" type="text" name="username">
<br />
<br />
<input placeholder="password" type="password" name="password">
<br />
<br />
<input value="Login" type="submit" name="log_In">
</form>
<div align="right">
<div>
<p>
<h2>Sign Up</h2>
</p>
<p>
<form method="post">
<input placeholder="Forename" type="text" name="fname" id="Forename">
<br />
<br />
<input placeholder="Surname" type="text" name="sname">
<br />
<br />
<input placeholder="Student Id" type="text" name="studId">
<br />
<br />
<input placeholder="Username" type="text" name="uname">
<br />
<br />
<input placeholder="password" type="password" name="pass" min="6" max="32">
<br />
<br />
<input placeholder="Re-type password" type="password" name="rpass" min="6" max="32">
<br />
<br />
<input placeholder="Email" type="" name="email">
<br />
<br />
<input placeholder="Re-type Email" type="remail" name="remail">
<br />
<br />
<input value="Sign Up" type="submit" name="sign_Up">
</form>
</p>
</div>
</div>

Answer 2

You forgot to add method="post"
<form method="post">
<input placeholder="Forename" type="text" name="fname" id="Forename"><br /><br />
<input placeholder="Surname" type="text" name="sname"><br /><br />
<input placeholder="Student Id" type="text" name="studId"><br /><br />
<input placeholder="Username" type="text" name="uname"><br /><br />
<input placeholder="password" type="password" name="pass" min="6" max="32"><br /><br />
<input placeholder="Re-type password" type="password" name="rpass" min="6" max="32"><br /><br />
<input placeholder="Email" type="" name="email"><br /><br />
<input placeholder="Re-type Email" type="remail" name="remail"><br /><br />
<input value="Sign Up" type="submit" name="sign_Up">
</form>

Answer 3

in second form you have not define the method if method is not defined it will accept the GET method default so change your second form tag by
<form action="" method="POST">