if (document.layers)
    document.captureEvents(Event.KEYPRESS);

function process_keypress(e) {
    if(window.event){
	if (window.event.type == "keypress" & window.event.keyCode == 13)
	    return !(window.event.type == "keypress" & window.event.keyCode == 13);
    }
    if(e){
	if (e.type == "keypress" & e.keyCode == 13)
	    return !e;
    }
}
document.onkeypress = process_keypress;