You can use following snippet:
var keys = {};
$('input').keydown(function (e) {
keys[e.which] = true;
});
$('input').keyup(function (e) {
getKeys();
delete keys[e.which];
});
function getKeys() {
if(keys[8]) {
alert('bakspace pressed');
}else if(keys[17] && keys[18] && keys[48]) {
alert('@ pressed');
}else if(keys[17] && keys[18] && keys[51]) {
alert('# pressed');
}
}
DEMO
original post: https://stackoverflow.com/a/4954480/1414562