Small Hide/show Region Bug

Hoping someone could solve this small problem of mine. I have numerous regions on a page that can be hidden/shown, the problem is i get a 'Line 8 Character 30 'id' is not defined' javascript browser error, but it works!

here is the code the error appears in:

PHP Code:
<script language="javascript" type="text/javascript">
/* This goes in the head section */
window.onload = function() { document.getElementById(id).style.display = 'none' }

function toggle(link, id) {
    var div = document.getElementById(id);
    if (div.style.display == 'none') {
        div.style.display = 'block'
        link.innerHTML = 'Hide Forms'
    } else {
        div.style.display = 'none'
        link.innerHTML = 'Show Forms'
    }
}
</script>

The code for the hide/show region is below.

PHP Code:
[ <a href="#id3" onclick="toggle(this, 'id3'); return false;">Show Forms</a> ]</div>
<div id="id3" style="padding: 10px; display: none;">
SHOW/HIDE CONTENT HERE!
</div>