(function() {
	function convert(inText) {
		var outText = '';
		var t;
		for (i = 0; i < inText.length; i++) {
			t = inText.charCodeAt(i);
			if ((t > 64 && t < 78) || (t > 96 && t < 110)) {
				t += 13;
			} else if ((t > 77 && t < 91) || (t > 109 && t < 123)) {
				t -= 13;
			}
			outText += String.fromCharCode(t);
		}
		return outText;
	}
	var sel = window.getSelection().getRangeAt(0);
	if (sel == '') {
		var act = document.activeElement;
		if (act.type == "textarea") {
			var start = act.selectionStart,
				end = act.selectionEnd;
			if (start != end) {
				var prefix = act.value.substring(0, start);
				var middle = convert(act.value.substring(start, end));
				var suffix = act.value.substring(end);
				act.value = prefix;
				act.value += middle;
				void(act.value += suffix);
			}
		} else {
			void(inText = prompt('Phrase...', ''));
			if (inText) alert(convert(inText));
		}
	} else {

		var S = window.getSelection();

		function t(N) {
			return N.nodeType == N.TEXT_NODE;
		}

		function r(N) {
			if (t(N)) {
				N.data = convert(N.data);
			}
		}
		for (j = 0; j < S.rangeCount; ++j) {
			var g = S.getRangeAt(j);
			var e = g.startContainer;
			var f = g.endContainer;
			var E = g.startOffset;
			var F = g.endOffset;
			var m = (e == f);
			if (!m || !t(e)) { /* rot13 each text node between e and f, not including e and f. */
				q = document.createTreeWalker(g.commonAncestorContainer, NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT, null, false);
				q.currentNode = e;
				for (N = q.nextNode(); N && N != f; N = q.nextNode()) r(N);
			}
			if (t(f)) {
				f.splitText(F);
			}
			if (!m) {
				r(f);
			}
			if (t(e)) {
				r(k = e.splitText(E));
				if (m) f = k;
				e = k;
			}
			if (t(f)) {
				g.setEnd(f, f.data.length);
			}
		}

	}
})();


//minified and ready to be a bookmarklet
javascript:(function(){function%20e(e){var%20t,n="";for(i=0;i<e.length;i++)(t=e.charCodeAt(i))>64&&t<78||t>96&&t<110?t+=13:(t>77&&t<91||t>109&&t<123)&&(t-=13),n+=String.fromCharCode(t);return%20n}function%20t(e){return%20e.nodeType==e.TEXT_NODE}function%20n(n){t(n)&&(n.data=e(n.data))}if(""==window.getSelection().getRangeAt(0)){var%20r=document.activeElement;if("textarea"==r.type){var%20a=r.selectionStart,o=r.selectionEnd;if(a!=o){var%20l=r.value.substring(0,a),u=e(r.value.substring(a,o)),d=r.value.substring(o);r.value=l,r.value+=u,r.value+=d}}else%20inText=prompt("Phrase...",""),inText&&alert(e(inText))}else{var%20s=window.getSelection();for(j=0;j<s.rangeCount;++j){var%20c=s.getRangeAt(j),f=c.startContainer,g=c.endContainer,v=c.startOffset,T=c.endOffset,E=f==g;if(!E||!t(f))for(q=document.createTreeWalker(c.commonAncestorContainer,NodeFilter.SHOW_ELEMENT|NodeFilter.SHOW_TEXT,null,!1),q.currentNode=f,N=q.nextNode();N&&N!=g;N=q.nextNode())n(N);t(g)&&g.splitText(T),E||n(g),t(f)&&(n(k=f.splitText(v)),E&&(g=k),f=k),t(g)&&c.setEnd(g,g.data.length)}}})();