Here is a solution for your problem http://jsfiddle.net/dima_k/zPv2a/
$('button').click(function(){
debugger
var e = $.Event("keypress");
e.keyCode = 13; // # Some key code value
$('#textbox').trigger(e);
});
$('#textbox').keypress(function(e)
{
if (e.keyCode == '13') {
alert('code');
}
});