[devote]

<div id="lala"></div>
<script type="text/javascript">
document.addEventListener( 'keydown', function( e ) {
    if ( e.ctrlKey && e.keyCode === 32 ) {
        document.getElementById( 'lala' ).innerHTML = "Вы нажали ctrl+space";
        e.preventDefault();
    }
}, false );
</script>