// código para fazer o enter agir como tab
window.onload=function(){

var coll=document.forms[0].elements;
for(i=0;i<coll.length;i++){
if(document.all){
coll[i].attachEvent("onkeypress",tabOnEnter);
}else{
coll[i].addEventListener("keypress",tabOnEnter,false);
}
}
}

function tabOnEnter(e){
if(document.all){
key=event.keyCode;
inp=event.srcElement.name;
idx=parseInt(event.srcElement.getAttribute("tabindex"));
}else{
key=e.which;
inp=e.target.name;
idx=parseInt(e.target.getAttribute("tabindex"));
}

if(key==13){
if(document.all){
event.cancelBubble=true;
}else{
e.stopPropagation();
}

var coll=document.forms[0].elements;
for(i=0;i<coll.length;i++){
if(idx!=""){
if(parseInt(coll[i].getAttribute("tabindex"))==idx+1){
coll[i].focus();
}
}else{
if(inp==coll[i].name){
nextel=i+1;
if(coll[nextel]){

coll[nextel].focus()}
}
}
}
return false;
}

}