Simple Plugin with custom javascript wont work – no console error

You could “borrow” the html form from the example and include this in your template – either directly of via a filter like wp_footer:

<form method="GET" action="/javascript/search-highlight/" onsubmit="myHilitor.apply(hilite.value); return false;">
<fieldset>
<legend>Highlight Words</legend>
<label>Keywords</label><span><input type="text" size="32" name="hilite" value="search engine keywords">
<input type="submit" value="Apply">
<input type="button" value="Remove" onclick="myHilitor.remove();"></span>
</fieldset>
</form>