Php回显html div无法正常工作[关闭]

I am trying to echo a welcoming message of Welcome (the user's name)! and I have done this fine on a php file just plain flat out echoing it. On my index.html file however when I use the same code trying to surround it with a div it does not work... Is it my concatenation? Why is this and how can I fix it?

<!---Sale Box--->
<center>
<div id="box">

<?php

session_start();
echo '<div id="text"> Welcome' . $_SESSION['username']. "</div>"

?>

</div>
</center>

you must use session_start before any output.

http://php.net/manual/en/function.session-start.php : " Note: To use cookie-based sessions, session_start() must be called before outputing anything to the browser." .

change index.html to index.php

PHP cant be parsed in .html-files. Only if you reconfigure your Apache-Server to handle .html as same as he does with .php.

So your page must be index.php instead of index.html

Also you should take care to run this on a server where a apache is running or may install a local apache server to parse php. See xampp

After this you have to echo like this (one possibility)

<?php session_start(); ?>
<!---Sale Box--->
<center>
<div id="box">

<?php echo "<div id='text'>Welcome {$_SESSION['username']}</div>"; ?>
</div>
</center>