// ==UserScript==
// @name        4chan Ø
// @namespace   4chan-ø
// @version     1.3
// @grant       none
// @match       http*://boards.4chan.org/*
// @include     http*://boards.4chan.org/*
// ==/UserScript==

var isFirefox = navigator.userAgent.toLowerCase().indexOf('firefox') > -1;

window.onload = function() {
        window.onkeyup = function(e) {
                if (e.target.tagName.toLowerCase() === 'textarea') {
                        if (isFirefox) {
                                if (e.key.toLowerCase() !== 'ø') {
                                        return;
                                }
                        } else {
                                if (e.keyCode !== 186 && e.keyCode !== 192) {
                                        return;
                                }
                        }

                        var elem = e.target;

                        var pos = elem.selectionStart;

                        elem.value = elem.value
                                .replace(/Ø/g, 'Ǿ')
                                .replace(/ø/g, 'ǿ');

                        elem.setSelectionRange(pos, pos);
                }
        };
};