Getting element node based on Javascript element based on position

I am experimenting with a Javascript function which stuffs nodes int开发者_JS百科o a position. Something like appendChild(document.getElementById("foo")) . However, I do not have full control over the surrounding code and it is likely that some elements will have identical IDs. Consider the following:

<div id="foo">
<span id = "bar">456</span>
<script type="text/javascript">document.write(document.getElementById("bar").innerText);</script>
</div>

<hr>

<div id="foo">
<span id = "bar">123</span>
<script type="text/javascript">document.write(document.getElementById("bar").innerText);</script>
</div>

In most browsers, the output will be:

456 456 
123 456

rather than what I want, which is

456 456 
123 123

This result is totally unsurprising to me; I do understand why this is happening. I was hoping I could do a javascript call more like

document.write(myscriptnode.parent.childnodes['bar'].innerText)

Assuming I do not have control over anything except the contents of the script tags, is there a way to accomplish this?

Here is an incredibly horrifying way to solve this problem: Rather than trying to get the current node, create a new node with an arbitrary ID, then delete it when done.

<div id="foo">
<span id = "bar">456</span>
<script type="text/javascript">
    document.write('<span id = "bfrogtmp"></span>');
    var y = document.getElementById("bfrogtmp");
    document.write(y.parentNode.children['bar'].innerHTML);
    y.parentNode.removeChild(y);
</script>
</div>

<hr>

<div id="foo">
<span id = "bar">123</span>
<script type="text/javascript">
    document.write('<span id = "bfrogtmp"></span>');
    var y = document.getElementById("bfrogtmp");
    document.write(y.parentNode.children['bar'].innerHTML);
    y.parentNode.removeChild(y);
</script>
</div>

How about using a JavaScript library like jQuery, which allows you to write CSS-selector-like-syntax insead of getElementById, and also has useful helper methods such as parent().

http://jquery.com/