If searching for contents in main view, the rendering of comments (if activated) use:
document.write
But this instruction that add text in the html when called during rendering, will just blow up the whole page when called after the end of the rendering.
So when such an inscrtruction is loaded in ajax, the whole page is blown up
document.write is not a good pattern in general.
We used it for accessibility purposes, but script and acccessility are now better friends so as a workaround you can add this in your ovverride of "cms/pages/comments/comments_3.3.xsl"