twitter-oauth-caution.user.js

// ==UserScript==
// @name Twitter OAuth Caution
// @namespace http://github.com/mooz/
// @description Display caution when application requests a 'write' access
// @include http://twitter.com/oauth/authorize?*
// @include http://twitter.com/oauth/authenticate?*
// @include https://twitter.com/oauth/authorize?*
// @include https://twitter.com/oauth/authenticate?*
// @include http://api.twitter.com/oauth/authorize?*
// @include http://api.twitter.com/oauth/authenticate?*
// @include https://api.twitter.com/oauth/authorize?*
// @include https://api.twitter.com/oauth/authenticate?*
// ==/UserScript==

(function () {
     const msgElem = document.querySelector(".signin-content > h4");
     const msgText = msgElem.textContent;
     const writeRequired = ["update", "\u66F4\u65B0"].some(function (w) { return msgText.indexOf(w) !== -1; });
     const readOnly = ["to access your", "\u306B\u30A2\u30AF\u30BB\u30B9\u3057\u3088\u3046\u3068"]
         .some(function (w) { return msgText.indexOf(w) !== -1; });

     if (!writeRequired && !readOnly)
         return;

     function p(text, style) {
         const p = document.createElement("p");
         p.textContent = text;
         p.setAttribute("style", style);

         return p;
     }

     const acsType = (writeRequired ? "Write" : "Read Only");
     const bgColor = (writeRequired ? "#ae0008" : "#fbd71c");
     const fgColor = (writeRequired ? "#ffffff" : "#000000");

     const caution = document.createElement("div");
     caution.setAttribute("style", ["-moz-border-radius    : 3px;",
                                    "-webkit-border-radius : 3px;",
                                    "border-radius         : 3px;",
                                    "padding               : 10px;",
                                    "margin                : 10px;",
                                    "background-color      : " + bgColor + ";",
                                    "-moz-box-shadow       : 0px 0px 3px #353535;",
                                    "-webkit-box-shadow    : 0px 0px 3px #353535;",
                                    "box-shadow            : 0px 0px 3px #353535;",
                                    "text-align            : center"].join("\n"));

     caution.appendChild(p("CAUTION", "color : " + fgColor + "; font-weight : bold; font-size : 40px;"));
     caution.appendChild(p("This application is requesting a '" + acsType + "' access",
                           "color : " + fgColor + "; font-size : 17px;"));

     msgElem.parentNode.insertBefore(caution, msgElem.nextSibling);
 })();