Hm.. I'm curious why this was needed (fearing what I may have to change in my own code). Which change in jQuery is this accommodating for?

http://blog.jquery.com/2014/01/24/jquery-1-11-and-2-1-released/

It looks as though previous behaviour of contents allowed for method arguments, but the current docs specify this method currently does not take any. Perhaps it was relying on an undocumented feature?

It could have been a regression from prior to 1.11.1

From at least jQuery 1.4 up to and including 1.11.1, the jQuery#contents method is implemented as part of a loop generating multiple methods. It still includes a selector arguments even now (which is indeed an documented feature and just a side-effect of the implementation re-using part of the code, should not be relied upon).

However, undocumented or not, from what I see it's been there since at least jQuery 1.4 and is still there in jQuery 1.11.1:

    contents: function( elem ) {
        return jQuery.nodeName( elem, "iframe" ) ?
            elem.contentDocument || elem.contentWindow.document :
            jQuery.makeArray( elem.childNodes );
    }
}, function( name, fn ) {
    jQuery.fn[ name ] = function( until, selector ) {
        var ret = jQuery.map( this, fn, until );

        if ( !runtil.test( name ) ) {
            selector = until;
        }

        if ( selector && typeof selector === "string" ) {
            ret = jQuery.filter( selector, ret );
        }

And testing shows it still seems to works:

$('body').contents();
> [ <pre> ]
$('body').contents( 'div' );
> []
$('body').contents( 'pre' );
> [ <pre> ]

Anyway, it makes sense now. The argument is not officially supported and therefore shouldn't be used.

I thought maybe the issue was more subtle (eg. :not() no longer being supported in some cases, or something like that). Just wanted to know exactly what part of the old code you were moving away from, so that I can look for it in my own code.

Thanks!