Duolingo Userscript for setting custom daily XP goals

goal-setter.user.js

// ==UserScript==
// @name         Custom Goal Setter
// @namespace    http://duolingo.com/skelkingur
// @version      0.1
// @description  Adds a new field to add a custom daily goal.
// @author       Fabian Becker <[email protected]>
// @match        https://www.duolingo.com/settings/*
// @grant        none
// ==/UserScript==


function attachCustomGoal() {
    if ($("#xp-custom").length !== 0) {
        return;
    }
    
    var el = $('.goal-chooser'),
        item = '<li><label class="btn btn-standard btn-small btn-outline daily-goal-option"><input id="xp-radio" name="daily_goal" data-goal="100" type="radio"> <span class="title">Custom</span> <span class="xp-text"><input id="xp-custom" type="number" style="width:50px;"></input>&nbsp; XP per day</span></label></li>',
        dailyGoal = duo.user.attributes.daily_goal;
    
    el.append(item);
    
    $("#xp-custom").click(function() {
       $("#xp-radio").attr('checked', true); 
    });
    
    $("#xp-custom").blur(function() {
       var radio = $("#xp-radio"),
           input = $("#xp-custom");
        
       radio.data("goal", input.val());
    });
    
    if ([1,10,20,30,50].indexOf(dailyGoal) == -1) {
       $("#xp-radio").attr('checked', true);
       $("#xp-custom").val(dailyGoal);
    } else {
        $("#xp-custom").val(100);
    }
}

$("#coach_tab").mouseup(function() {
    // This is silly
    setTimeout(attachCustomGoal, 100);
});
$(document).ready(attachCustomGoal);
$(document).ajaxComplete(attachCustomGoal);