jQuery slideDown / slideUp代码仅在CTRL + F5之后有效吗？

Question

This problem has bothered me for many hours now, and I hope somebody can help me.

I have the following code, which opens and closes a recursive UL menu. It works everywhere, except IE9. However, it only works when I refresh the page with CTRL+F5. If I don't refresh with CTRL+F5 I get a bunch of errors like the following:

• SCRIPT5022: DOM Exeption: SYNTAX_ERR (12); (refering to if (currentLink))
• SCRIPT5022: DOM Exeption: SYNTAX_ERR (12); (refering to currentLink.parent().find)

Does anybody know what's going on here?

    $('.groups').find('li:has(ul)').find('.uitklapTrigger').click(function(){
    var currentLink = $(this);
    if (currentLink.parent().find('ul').first().is(":hidden")){
        currentLink.children('.plmin').html('-');
        currentLink.parent().find('ul').first().slideDown('slow');
    } else {
        currentLink.parent().find('ul').first().slideUp("slow", function(){
            currentLink.children('.plmin').html('+');
        });
    }

    return false;
});

Answer 1

The answer is clear. It had to do with some IE9 setting. Miraculously the pc's on which I tested both had some strange (acer factory default) browser settings. I had reset the browser settings and the problem was solved... Thanks everybody.