jquery 兼容　ie和firefox上的　change enter to tab
$(document).keydown(function(event){
if(event.which==13){
if($.browser.msie) {//IE
window.event.keyCode=9;
}else//其它只测了fireforx
{
var $target = $(event.target);
var textboxes = $("input,select");
var currentBoxNumber = textboxes.index($target);

if (textboxes[currentBoxNumber + 1] != null) {
var nextBox = textboxes[currentBoxNumber + 1]
nextBox.focus();
nextBox.select();

}else{
var nextBox = textboxes[0]
nextBox.focus();
nextBox.select();
}

event.preventDefault();
return false;
}
}
//说明，对于firefox的做得不完善，希望今后有人看到了提示一下或者发现更好的更新一下