HTML Excerpt causing issues [closed]

Question

Hi I have this code to give me an HTML version of the excerpt box on the edit post screen, however when I'm in the HTML tab of the editor and switch to Visual I only see a blank page. Reloading the page fixes it. The issue is definitely caused by this code as without it everything works fine. Any idea what needs to be fixed here?

function tinymce_excerpt_js(){ ?>
    <script type="text/javascript">
            jQuery(document).ready( tinymce_excerpt );
                function tinymce_excerpt() {
                    jQuery("#excerpt").addClass("mceEditor");
                    try {
                    tinyMCE.execCommand("mceAddControl", false, "excerpt");
                    tinyMCE.onAddEditor.add(function(mgr,ed) {
                        if(ed.id=="excerpt"){
                            ed.settings.theme_advanced_buttons2 ="";
                            ed.settings.theme_advanced_buttons1 = "bold,italic,underline,seperator,justifyleft,justifycenter,justifyright,separator,link,unlink,seperator,pastetext,pasteword,removeformat,seperator,undo,redo,seperator,spellchecker,";
                        }
                    });
                    } 
                    catch(e) {
                    // ignore
                    }                        
                }
    </script>
<?php }
add_action( 'admin_head-post.php', 'tinymce_excerpt_js');
add_action( 'admin_head-post-new.php', 'tinymce_excerpt_js');

function tinymce_css(){ ?>
    <style type='text/css'>
        #postexcerpt .inside{margin:0;padding:0;background:#fff;}
        #postexcerpt .inside p{padding:0px 0px 5px 10px;}
        #postexcerpt #excerpteditorcontainer { border-style: solid; padding: 0; }
    </style>
<?php }
add_action( 'admin_head-post.php', 'tinymce_css');
add_action( 'admin_head-post-new.php', 'tinymce_css');

function prepareExcerptForEdit($e){
    return nl2br($e);
}
add_action( 'excerpt_edit_pre','prepareExcerptForEdit');