userscripts/Elements with ID lister.user.js

// ==UserScript==
// @name        Elements with ID lister
// @namespace   blankie-scripts
// @match       *://*/*
// @grant       GM_registerMenuCommand
// @grant       GM_getResourceURL
// @require     https://cdn.jsdelivr.net/npm/dialog-polyfill@0.5.6/dist/dialog-polyfill.min.js#sha256-cec1a2e320aab77e28bad4ad6bc5e532a6ef5757345c19bb5158aa880b7162a6
// @resource    dialogPolyfillCSS https://cdn.jsdelivr.net/npm/dialog-polyfill@0.5.6/dist/dialog-polyfill.min.css#sha256-4dcb3ab62e545f30bf06a4824c253641ee889ca85ca28d5447590557922496ab
// @version     1.0.6
// @author      blankie
// @description A userscript that adds a "Show elements popup" option to the Monkey Menu which lists all elements with an ID
// @inject-into content
// ==/UserScript==

"use strict";

const DIALOG_WRAPPER_ID = "element_lister-dialog_wrapper";
const ACCENT_COLOR = "#962AC3";
const BRIGHT_ACCENT_COLOR = "#DE6DE6";

const DIALOG_WRAPPER_CSS = `
    position: fixed;
    top: 0;
    width: 100%;
    height: 100%;
`;
const CSS = `
dialog {
    position: fixed;
    min-width: 25em;
    max-height: 90%;
    font-size: 11pt;
    color-scheme: dark;
    overflow-y: auto;
}
dialog, dialog.polyfilled button {
    color: white;
    background-color: black;
}
dialog.polyfilled {
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}
dialog::backdrop, dialog + .backdrop {
    background-color: rgba(0, 0, 0, .5);
}

.align-right {
    text-align: right;
}

a {
    color: ${ACCENT_COLOR};
    text-decoration: none;
}
a:hover {
    color: ${BRIGHT_ACCENT_COLOR};
    text-decoration: underline;
}
`;

function showElementList() {
    if (document.getElementById(DIALOG_WRAPPER_ID)) {
        return;
    }

    let dialogWrapper = document.createElement("div");
    dialogWrapper.id = DIALOG_WRAPPER_ID;
    dialogWrapper.style = DIALOG_WRAPPER_CSS;
    let shadowRoot = dialogWrapper.attachShadow({mode: "closed"});

    let link = document.createElement("link");
    link.rel = "stylesheet";
    link.href = GM_getResourceURL("dialogPolyfillCSS");
    shadowRoot.append(link);

    let style = document.createElement("style");
    style.textContent = CSS;
    shadowRoot.append(style);

    let dialog = document.createElement("dialog");
    if (!dialog.showModal) {
        dialog.classList.add("polyfilled");
    }
    dialogPolyfill.registerDialog(dialog);
    dialog.addEventListener("close", hideElementList, {once: true, passive: true});
    dialogWrapper.addEventListener("click", function(e) {
        let rect = dialog.getBoundingClientRect();
        if (rect.top <= e.clientY && rect.left <= e.clientX && rect.bottom >= e.clientY && rect.right >= e.clientX) {
            return;
        }
        hideElementList();
    }, {passive: true});

    let buttonWrapper = document.createElement("div");
    buttonWrapper.classList.add("align-right");
    let button = document.createElement("button");
    button.textContent = "Close";
    button.addEventListener("click", hideElementList, {once: true, passive: true});
    buttonWrapper.append(button);
    dialog.append(buttonWrapper);

    let hr = document.createElement("hr");
    dialog.append(hr);

    let elements = getElementList();
    if (elements.length) {
        let ul = document.createElement("ul");
        for (let i of getElementList()) {
            ul.append(i);
        }
        dialog.append(ul);
    } else {
        dialog.append("There are no elements with an ID.");
    }

    shadowRoot.append(dialog);
    document.body.append(dialogWrapper);
    dialog.showModal();
}

function hideElementList() {
    let dialogWrapper = document.getElementById(DIALOG_WRAPPER_ID);
    if (!dialogWrapper) {
        return;
    }

    dialogWrapper.remove();
}



function getElementList() {
    let elements = [];

    for (let element of document.body.querySelectorAll("[id]")) {
        if (shouldIgnoreElement(element)) {
            continue;
        }
        elements.push(getElementListItem(element));
    }

    return elements;
}

function shouldIgnoreElement(element) {
    // Check if the element is not visible
    let rect = element.getBoundingClientRect();
    if (rect.height === 0 || rect.width === 0) {
        return true;
    }

    // Check if the element is a svg or a part of one
    // https://arstechnica.com/information-technology/2023/05/critics-say-googles-new-zip-and-mov-domains-will-be-a-boon-to-scammers/
    while (element) {
        if (element.localName === "svg") {
            return true;
        }
        element = element.parentElement;
    }

    return false;
}

function getElementListItem(element) {
    let li = document.createElement("li");

    let a = document.createElement("a");
    a.href = a.innerText = "#" + element.id;
    a.addEventListener("click", function(e) {
        if (e.ctrlKey) {
            return;
        }
        hideElementList();
    }, {passive: true});
    li.append(a);

    let description = getElementDescription(element);
    if (description) {
        li.append(" (", description, ")");
    }

    return li;
}

function getElementDescription(element) {
    let addEilipses = false;
    let text = (element.innerText || "").trim();

    let newlineIndex = text.indexOf("\n");
    if (newlineIndex !== -1) {
        text = text.substring(0, newlineIndex);
        addEilipses = true;
    }

    if (text.length > 50) {
        text = text.substring(0, 50);
        addEilipses = true;
    }

    if (addEilipses) {
        text += "...";
    }
    return text;
}



GM_registerMenuCommand("Show elements popup", function() {
    if (!document.getElementById(DIALOG_WRAPPER_ID)) {
        showElementList();
    } else {
        hideElementList();
    }
})