// Unset unwanted Scripts - by name
$unset_scripts = array(
	'k2',
	'...',
);
foreach($this->_scripts as $name=>$script)
{
	if (!preg_match('#(' . implode('|', $unset_scripts) . '#i', $name))
	{
		continue;
	}
	unset($this->_scripts[$name]);
}

or if you use joomla v3.8.1 you can try this php code:

<?php
	$doc = JFactory::getDocument();
	unset($doc->_scripts[JURI::root(true) . '/media/system/js/mootools-more.js']);
	unset($doc->_scripts[JURI::root(true) . '/media/system/js/mootools-core.js']);
	unset($doc->_scripts[JURI::root(true) . '/media/system/js/core.js']);
	unset($doc->_scripts[JURI::root(true) . '/media/system/js/modal.js']);
	unset($doc->_scripts[JURI::root(true) . '/media/system/js/caption.js']);
	unset($doc->_scripts[JURI::root(true) . '/media/jui/js/jquery.min.js']);
	unset($doc->_scripts[JURI::root(true) . '/media/jui/js/jquery-noconflict.js']);
	unset($doc->_scripts[JURI::root(true) . '/media/jui/js/bootstrap.min.js']);
?>

if you wand disable all js & css scripts - use code:

$doc->_scripts     = null;
$doc->_script      = null;
$doc->_styleSheets = null;

How use keyboard events? It's simple:

<script>
    	$(document).ready(function() {
	  		$(window).keydown(function(event){
	    		if(event.keyCode == 13) {
	      			event.preventDefault();
	      			return false;
	    		}
	 		 });
		});
</script>