Show "only on index" code?

[qbn720]

Hey guys, I need a code that goes into my header that will only show a certain line of code when it is on index.php (the homepage). I tried using a simple php code:

<?php
if (stristri($_SERVER['REQUEST_URI'], 'index.php') !== FALSE) {
CODE HERE
}
?>

but it returns a syntax error. Does anyone know how I can go about accomplishing what I need? Thanks!