PHP $ _SESSION变量不成立

Question

I'm not great at this stuff as will be evident, but would like to try and get better. I have a wedding website for my fiancé and I, that I'm having troubles with. I have a simple login on the index that goes through a login page, login confirmation page and back to the index. It will hold the $_SESSION['name' variable from the form, confirmed in mysql, back to the index but not to anywhere else. Even in refreshing that page, it will disappear.

index.php

  <div id="login">
        <span class="login">
            <form action="login.php" method="post" id="loginform">
                <label for="name">User:</label>
                <input type="text" name="name" id="name" size="12">
                <label for="password">Password:</label>
                <input type="password" name="password" id="password" size="12">
                <input type="submit" value="submit" id="submit">
                <input type="button" value="hide" id="hide" onclick="loghide()">
            </form>
        </span>
    </div>
    <br />
    <div id="logged">
        <?php
if (isset($_SESSION['username'])){
echo "<script      type='text/javascript'>document.getElementById('logged').style.cssText='opacity:1;-webkit-transition:1s;-moz-transition:1s;-o-transition:1s;-ms-transition:1s;transition:1s;';</script>";
echo "<script    type='text/javascript'>document.getElementById('login').style.cssText='display:none;';</script>";
}      
?>
        <span class="logged">
                <ul id="adminlinks">
                    <div id="event">
                        <div id="hiddenlinks">
                            <li><a class="links" id="hidden2"     href="events.html">index</a></li>
                            <br />
                            <li><a class="links" id="hidden3"      href="events.html">our story</a></li>
                            <br />
                        </div>
                        <li><a class="links">update</a></li>
                    </div>
                    <li><a class="links" href="addphotos.php">add     photos</a></li>
                       <li><a class="links" href="<?php session_destroy(); header("Location:index.php"); ?>">Log Out</a></li>
                </ul>
        </span>
    </div>
</div>
<div id="bottom">
    <span class="foot">july fourth, two thousand and fifteen</span>
</div>
</div>

<?php
echo $_SESSION['username'];
echo $myusername;
?>

login.php

////deleted mysql connection stuff
session_start();
$_SESSION['username']=$myusername;
$_SESSION['password']=$mypassword; 
header("location:login_success.php");
}
else {
echo "Wrong Username or Password";
}
?>

login_success.php

<?php
session_start();
if (!isset($_SESSION['username'])){
echo "nope";
} else {header("location:index.php");}

?>

I have session_start()'s at the tops of those pages swell. It will work right there but then moving to my next admin link it won't. I had the echo $_SESSION['username']; at the bottom to see if it was registered.

Its hosted on GoDaddy which does save session stuff in a root/tmp folder so there is a path for it. I'm at a loss.

Any ideas for a noob?

It's not an important login or anything as it would just be me or my fiancé logging in to update pictures or something but wanted to do it myself and make it nice.

Thanks, Matt

Edit- Index.php and addphotos.php have session_start(); at the top of the page.

the next admin link as I called it is addphotos.php basically the same as the index with other content to be added later.

Double Edit - Was going to encrypt passwords. Would there be a better way to accomplish things without $_SESSION variables? What if only the $_SESSION['username'] was set but not a password one?

FINAL- Okay thanks everyone! Got it and am revamping things.

Answer 1

<a class="links" href="<?php session_destroy(); header("Location:index.php");?>">Log Out</a>

This is not creating a link to this code, you're actually running it! Create a logout.php page with this code in it, and link to that page instead. This is why your session is being destroyed. You also need session_start() on all pages that use sessions.

Answer 2

You must call session_start(); on the index page in order to use it there, the sessions are kept, it's just that you need to tell the program to start the session and so it will use the values found there. put the following code on the first line of your index.php file:

<?php session_start(); ?>

Hope it helps.