A bookmarklet to add extra speed options to the echo player (supports x0-16, up to a reasonable number of decimal places)

__echoUtil__speed__.js

if (!window.__echoUtil__speed__) {
    window.__echoUtil__speed__ = {};

    __echoUtil__speed__.createOptionEl = function (speed) {
        var optionEl = document.createElement("option");
        optionEl.value = speed;
        optionEl.text = optionEl.value;
        return optionEl;
    };

    __echoUtil__speed__.updateOptions = function () {
        var l = document.querySelector("#speed-select");
        l.innerHTML = "";
        for (var i = 0; i < __echoUtil__speed__.insertedSpeeds.length; i++) l.appendChild(__echoUtil__speed__.insertedSpeeds[i]);
        l.value = 0;
    };

    __echoUtil__speed__.settingsWheelEl = document.getElementsByClassName("echoPlayer")[0].querySelector("div > div > div.controls > div.controlsBar > div.right > div.video-menu.settings-menu > a");

    __echoUtil__speed__.settingsWheelEl.click();
    __echoUtil__speed__.insertedSpeeds = Array(__echoUtil__speed__.createOptionEl(0), ...document.querySelector("#speed-select").children);
    __echoUtil__speed__.settingsWheelEl.click();

    __echoUtil__speed__.isMenuOpen = function () { return !!document.querySelector("#speed-select"); };

    document.getElementsByClassName("echoPlayer")[0].querySelector("div > div > div.controls > div.controlsBar > div.right > div.video-menu.settings-menu > a").onclick = function () { setTimeout(() => { if (__echoUtil__speed__.isMenuOpen()) __echoUtil__speed__.updateOptions(); }, 10); };
}

var isOpen = __echoUtil__speed__.isMenuOpen();

var speed = parseFloat(prompt("New Speed Option Value"));
if (speed < 0) throw new Error("Negative speed breaks the lecture player (-_-)");
if (speed > 16) throw new Error("Too fast for the lecture player (<= x16)");
if (!(0 <= speed && speed <= 16)) throw new Error("Unprocessable type '" + speed + "' - please input a float between 0 and 16");

if (isOpen) __echoUtil__speed__.settingsWheelEl.click();

var optionEl = __echoUtil__speed__.createOptionEl(speed), f = __echoUtil__speed__.insertedSpeeds.findIndex(el => el.value >= speed);
if (f == -1) __echoUtil__speed__.insertedSpeeds.push(optionEl);
else if (__echoUtil__speed__.insertedSpeeds[f].value != speed) __echoUtil__speed__.insertedSpeeds.splice(f, 0, optionEl);

if (isOpen) __echoUtil__speed__.settingsWheelEl.click();

bookmarklet.js

javascript: window.__echoUtil__speed__||(window.__echoUtil__speed__={},__echoUtil__speed__.createOptionEl=function(e){var _=document.createElement("option");return _.value=e,_.text=_.value,_},__echoUtil__speed__.updateOptions=function(){var e=document.querySelector("#speed-select");e.innerHTML="";for(var _=0;_<__echoUtil__speed__.insertedSpeeds.length;_++)e.appendChild(__echoUtil__speed__.insertedSpeeds[_]);e.value=0},__echoUtil__speed__.settingsWheelEl=document.getElementsByClassName("echoPlayer")[0].querySelector("div > div > div.controls > div.controlsBar > div.right > div.video-menu.settings-menu > a"),__echoUtil__speed__.settingsWheelEl.click(),__echoUtil__speed__.insertedSpeeds=Array(__echoUtil__speed__.createOptionEl(0),...document.querySelector("#speed-select").children),__echoUtil__speed__.settingsWheelEl.click(),__echoUtil__speed__.isMenuOpen=function(){return!!document.querySelector("#speed-select")},document.getElementsByClassName("echoPlayer")[0].querySelector("div > div > div.controls > div.controlsBar > div.right > div.video-menu.settings-menu > a").onclick=function(){setTimeout(()=>{__echoUtil__speed__.isMenuOpen()&&__echoUtil__speed__.updateOptions()},10)});var isOpen=__echoUtil__speed__.isMenuOpen(),speed=parseFloat(prompt("New Speed Option Value"));if(speed<0)throw new Error("Negative speed breaks the lecture player (-_-)");if(speed>16)throw new Error("Too fast for the lecture player (<= x16)");if(!(0<=speed&&speed<=16))throw new Error("Unprocessable type '"+speed+"' - please input a float between 0 and 16");isOpen&&__echoUtil__speed__.settingsWheelEl.click();var optionEl=__echoUtil__speed__.createOptionEl(speed),f=__echoUtil__speed__.insertedSpeeds.findIndex(e=>e.value>=speed);-1==f?__echoUtil__speed__.insertedSpeeds.push(optionEl):__echoUtil__speed__.insertedSpeeds[f].value!=speed&&__echoUtil__speed__.insertedSpeeds.splice(f,0,optionEl),isOpen&&__echoUtil__speed__.settingsWheelEl.click();