☰

Block OpenSearch Descriptions

Block sites from adding search engines to Chrome.

// ==UserScript==
// @name            Block OpenSearch Descriptions
// @author
// @description     Block sites from adding search engines to Chrome.
// @downloadURL
// @grant
// @icon
// @include         http*://*
// @require
// @run-at          document-start
// @updateURL
// @version         2.0
// @namespace https://greasyfork.org/users/218540
// ==/UserScript==

//document.querySelector('[type="application/opensearchdescription+xml"]').remove();
//////////////////////////////////////////////////////////////////////////////
// Code from https://github.com/gregsadetsky/chrome-dont-add-custom-search-engines/blob/master/src/content.js
// OpenSearch - e.g., https://martin-thoma.com/search-engine-autodiscovery/
// Uses CSS4 selectors, Chrome 49+
const DEBUG=false;
let numseen=0, numspoiled=0;
let unspoiled=[];

// called when the user clicks an element of the form (any field or button).
// The parameter passed is the event object.
function clickApply(e) {
    if(DEBUG) console.info({'form onclick':e});
    // remove onclick. One fix only
    e.srcElement.form.removeEventListener("click", clickApply);
    applyFix(e.srcElement.form);
} //clickApply

// add a new <textarea> element
function applyFix(elem) {
  var newelem = document.createElement('textarea');
  newelem.name = '';
  newelem.style.display='none';
  elem.appendChild(newelem);
} //applyFix

// Add an extra child input to any form that only has one
function spoilFormGet(elem) {
    if(DEBUG) {
        ++numseen;
        unspoiled.push(elem);
    }

    // Check whether the form submits to a HTTP(S) URL.
    // A missing or relative action will be resolved against the page URL
    // so it must have the same URI scheme which is all we care about
    var action = elem.getAttribute('action');
    if(!(action && action.indexOf('://') >= 0)) action = location.href;
    if(!/^https?:\/\//i.test(action)) return;

    // Autodetection requires exactly one input of type text or search
    // If the type attribute is missing, it defaults to `text`
    // Readonly inputs do not count against this total
    if(elem.querySelectorAll(':scope input:-webkit-any([type="text" i],[type="search" i],[type*="search" i],[type=""],:not([type])):not([readonly])[name]:not([name=""])').length !== 1) return;

    // Autodetection also requires no password, file, or textarea elements
    if(elem.querySelector(':scope :-webkit-any(input[type="password" i],input[type="file" i],textarea)')) return;

    // Add a <textarea> - unlike <input>, it doesn't block implicit submission
    // per https://www.tjvantoll.com/2013/01/01/enter-should-submit-forms-stop-messing-with-that/

    // apply the fix now, or place it in onclick.  "this" is a parameter passed by foreach(). see below
    if (this.now === true) {
        // remove onclick placed during first pass
        elem.removeEventListener("click", clickApply);
        // and instead do it now;
        applyFix(elem);
    } else {
        elem.addEventListener('click', clickApply);
    }

    if(DEBUG) {
        console.info({Spoiled: elem});
        ++numspoiled;
        unspoiled.pop();
    }
} //spoilFormGet

var debugAutoDetect=0;

// move this part of the code here, since it's called multiple times
function autoDetect(now, when_called) {
    if(DEBUG) console.log('autoDetect: '+(++debugAutoDetect)+' ('+when_called+')');
    document.querySelectorAll('form:-webkit-any([method="get" i],:not([method]))').forEach(spoilFormGet,{now});
    if(DEBUG) {
        console.log(`Spoiled ${numspoiled}/${numseen}.`+(unspoiled.length?'  Unspoiled were:':'') );
        if (unspoiled.length) console.log(unspoiled);
    }

    // we reset spoil vars for next call
    numseen=0;
    numspoiled=0;
    unspoiled=[];
} //autoDetect

function catchOpenSearch() {
    if(DEBUG) console.info('catchOpenSearch called');
    // OpenSearch - e.g., https://martin-thoma.com/search-engine-autodiscovery/
    // Uses CSS4 selectors, Chrome 49+
    document.querySelectorAll('[type="application/opensearchdescription+xml" i]').forEach(
        function (it) {
            it.removeAttribute('type');
            if(DEBUG) console.info({"Spoiled by type removal": it});
        }
    );

    // Suggestion service, https://www.chromium.org/tab-to-search
    document.querySelectorAll('url[rel="suggestions" i]').forEach(
        function (it) {
            it.removeAttribute('rel');
            if(DEBUG) console.info({"Spoiled by rel removal": it});
        }
    );
} //catchOpenSearch

function onDOMContentLoaded() {
    if(DEBUG) console.log('onDOMContentLoaded');

    catchOpenSearch();

    // #1 call it now (i.e., DOMContentLoaded) without applying the fix
    // #2 call it in 1500 ms and apply the fix
    // #3 call when document loaded, and apply the fix.

    // if <form> is added/modified // dynamically before the document
    // is fully loaded, #1 could miss it, but not #2 & #3. Note that #2
    // could fire after #3 if the page is fast to load.  Once the fix
    // is applied, the <form> can't be found by subsequent execution
    // of autoDetect, so the fix can only be applied once (#1 is not
    // applied but delayed until #2 or #3 fires, or if the user
    // clicks).

    window.addEventListener('load', function() {
        if(DEBUG) console.log('onload');
        catchOpenSearch();
        autoDetect(true,'Load');
    } );  // #3
    setTimeout(function() { autoDetect(true,'Timer'); } ,1500);     // #2
    autoDetect(false,'onClick');                                    // #1

} //onDOMContentLoaded

(function() {
    document.addEventListener('DOMContentLoaded', onDOMContentLoaded);
    onDOMContentLoaded();
})();