[jQuery] simple testing of selectors returning empty result

In many situations I use jQuery selector and I want to check that
result is non empty. To make this simple, I use this code:

// jQuery extension to test non-empty select
(function($)
{
    $.fn.notempty = function()
    {
        if (this.length==0)
            throw('Empty jQuery selector');
        return this;
    };
})(jQuery);

...and than use it like:

$("#someID").notempty().show().someotheroperation();

I use custom error handler for javascript errors:

window.onerror = function(desc,page,line,chr) { /* my error reporting
*/ }

...but uncaught exception does not end in this handler. Is there any
way to report file and line where this test failed (I mean file and
line with $("#someID").notempty()... from my example) ?

Thanks a lot for any hint.