Loss of Button Function Within Onload Script

I cannot figure out why navigation panel buttons are losing CSS formatting and their function as HTML buttons.

The page markup (in [B]index.html[/B]) is here:

[url]http://proteomics.dynalias.org/Tests/Regena/[/url]

There is one external [B]CSS[/B] and one external [B]JS[/B] file that contains all the

I have traced the problem to a single Javascript line during the initialization (first loading) of the document.

[CODE]
61: contentPanel.replaceChild(content, contentPanel.firstChild);
[/CODE]

This is line 61 in the function [B]jumpToPage()[/B] in the ncluded external Javascript file [B]ReGenaVetLabs.js[/B]

Up to this script statement, the buttons are active and the mouse cursor shows as a pointer. After it executes, the cursor is no longer a pointer, and the buttons not clickable.

It does not make sense to me why the left-side navigation buttons should be affected.

===================================
MORE INFORMATION

The page layout has four parts:

“(constant)” means it does not change from page to page.

Although there is only one physical page—which is index.html in this setup—the content is loaded using scripts: the page is full of text and images that are contained inside DIV elements whose display is turned off (style=”display:none;”) and the DIV content is loaded using Javascript, simply by using the DOM [B].replaceChild()[/B] method for the DIV element that makes contains panel labeled 3 above…the content panel.

Later on, I will make each page a separate HTML page, to deal with browsers whose script use is deliberately disabled. But this development is easier for me, and it avoids the new page loading appearance: browser window clears, browser loads wanted page.

Also in #JavaScript _↴