Fijate si te sirve:
Código javascript
:
Ver original<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>test</title>
<script>
function unir(){
var b=[];
for(var i=0;i< arguments.length;i++){
ii=0;
while (document.getElementsByTagName(arguments[i])[ii]){
b.push(document.getElementsByTagName(arguments[i])[ii]);
ii++;
}
}
return b;
}
onload=function(){
var x=unir('a','span');
alert(x[0].nodeName+'-'+x[2].nodeName+'-'+x[7].nodeName)
}
</script>
</head>
<body>
<span>a</span><a href="#">b</a><span>a</span><a href="#">b</a><span>a</span><a href="#">b</a><span>a</span><a href="#">b</a>
</body>
</html>