$("element").keydown(function(){
.....
})

• Video Tutorial on keyboard Events

<script>
$(document).ready(function() {
$(document).keydown(function(){
alert('hi');
});
})
</script>

Difference between keypress and keydown events ?

<script>
$(document).ready(function() {
//// keydown() ///
$(document).keydown(function(){
$('#d1').html('Keydown Event happened, keycode: '+ event.which);
$("#d1").show();
setTimeout(function() { $("#d1").fadeOut('slow'); }, 1000);
});
/////keypress() ///
$(document).keypress(function(){
$('#d2').html('Keypress Event happened, keycode: '+ event.which);
$("#d2").show();
setTimeout(function() { $("#d2").fadeOut('slow'); }, 1000);
});
///
});
</script>

 <div id=d1></div> <div id=d2></div>