1 (function(w) {

     2 	var init = function() {

     3 		var pr = document.getElementById('post-revisions'),

     4 		inputs = pr ? pr.getElementsByTagName('input') : [];

     5 		pr.onclick = function() {

     6 			var i, checkCount = 0, side;

     7 			for ( i = 0; i < inputs.length; i++ ) {

     8 				checkCount += inputs[i].checked ? 1 : 0;

     9 				side = inputs[i].getAttribute('name');

    10 				if ( ! inputs[i].checked &&

    11 				( 'left' == side && 1 > checkCount || 'right' == side && 1 < checkCount && ( ! inputs[i-1] || ! inputs[i-1].checked ) ) &&

    12 				! ( inputs[i+1] && inputs[i+1].checked && 'right' == inputs[i+1].getAttribute('name') ) )

    13 					inputs[i].style.visibility = 'hidden';

    14 				else if ( 'left' == side || 'right' == side )

    15 					inputs[i].style.visibility = 'visible';

    16 			}

    17 		}

    18 		pr.onclick();

    19 	}

    20 	if ( w && w.addEventListener )

    21 		w.addEventListener('load', init, false);

    22 	else if ( w && w.attachEvent )

    23 		w.attachEvent('onload', init);

    24 })(window);