The difference between jquery usage in IE and firefox_jquery

Can run under IE and Firefox.
//Enter event processing
$(document).keydown(function(event){
if(event.keyCode==13){
alert($('#idone').val());
//Enter keyboard to get ISBN
if($('#idone').val()=='isbn') {
//isbncheck();
$('#ztm').focus();
}else
if($('#idone').val()=='ztm '){
$('#bltm').focus();
}
if($('#idone').val()=='bltm'){
$( '#ftm').focus();
}else
if($('#idone').val()=='ftm'){
$('#dyzrsm').focus ();
}

}
});

can only be run under IE.
//Enter event handling
$(document).keydown(function(){
if(event.keyCode==13){
//alert($('#idone').val());
//return Car keyboard ISBN acquisition
if($('#idone').val()=='isbn'){
//isbncheck();
$('#ztm').focus() ;
}
if($('#idone').val()=='ztm'){
$('#bltm').focus();
}
if($('#idone').val()=='bltm'){
$('#ftm').focus();
}
}
});
In summary, debugging programs under Firefox is beneficial to program compatibility.