It could be something like this:
function anand657_hook_javascript() {
if (!is_page ('920')) {
?>
<script type="text/javascript">
// your javscript code goes here
</script>
<?php
}
}
add_action('wp_footer', 'anand657_hook_javascript');
PS: DON'T RUN THE ABOVE CODE ON LIVE SITE UNLESS YOU HAVE A BACKUP. it might break your site if any thing goes wrong. It's good to have backup handy.