I was looking at [this timeline](http://stackoverflow.com/admin/posts/timeline/39442238) for very boring, uninteresting reasons. The JS (and, consequently, responsive elements) on that page is broken.

Console:

    VM3535:6 Uncaught ReferenceError: Invalid left-hand side in assignment
        at eval (<anonymous>)
        at http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js:2:11530
        at Function.globalEval (http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js:2:11541)
        at HTMLScriptElement.bp (http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js:2:3293)
        at Function.each (http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js:2:11937)
        at init.domManip (http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js:4:1920)
        at init.append (http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js:3:31818)
        at init.html (http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js:4:776)
        at HTMLSpanElement.<anonymous> (http://stackoverflow.com/admin/posts/timeline/39442238:1100:20)
        at Function.each (http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js:2:11937)(anonymous function) @ jquery.min.js:2globalEval @ jquery.min.js:2bp @ jquery.min.js:2each @ jquery.min.js:2domManip @ jquery.min.js:4append @ jquery.min.js:3html @ jquery.min.js:4(anonymous function) @ 39442238:1100each @ jquery.min.js:2each @ jquery.min.js:2(anonymous function) @ 39442238:1098n @ jquery.min.js:2fireWith @ jquery.min.js:2ready @ jquery.min.js:2B @ jquery.min.js:2

Which maps to this line:

    StackExchange.ready(function() {
        if (StackExchange.options.isMobile) return;

        $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() {
            var $hover = $(this).addClass('hover-bound')<br> // < This one
                $msg = $hover.siblings('.dupe-hammer-message');
            
            $hover.hover(
                function() {
                    $hover.showInfoMessage(''<br> {
                        messageElement: $msg.clone().show()<br>
                        transient: false<br>
                        position: { my: 'bottom left'<br> at: 'top center'<br> offsetTop: -7 }<br>
                        dismissable: false
                    });
                }<br>

Those `<br>`s are there in the actual code Chrome is showing, which doesn't look right.