Download video subtitles

injected.js

// Configs...
// YouTube video list.
var urls = `
https://www.youtube.com/watch?v=ev9zrt__lec



`;

// Process...

$ = null;

(function() {
    // Load the script
    const script = document.createElement("script");
    script.src = 'https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js';
    script.type = 'text/javascript';
    script.addEventListener('load', () => {
      console.log(`jQuery ${$.fn.jquery} has been loaded successfully!`);
      // use jQuery below
      $ = $;
      entry();
    });
    document.head.appendChild(script);
})();

var searchSubtitleInterval = null;
var enableRedirectInterval = null;
var enableRedirect = false;

function entry ()
{
    if (window.location.href.toString().indexOf('checksub.com') == -1)
        return false;

    // Startup control.
    var currentUrl = getUrlParameter('videoUrl');

    if (!currentUrl) {
        urls = urls.trim();
        urls = urls.split("\n");
        window.location.href = 'https://download.checksub.com/download?videoUrl='+ urls[0];
    }

    // Download control.
    $(document).ready(function(){
        console.log("Verbum started!");

        // Search subtitle element.
        searchSubtitleInterval = setInterval(function(){
            var els = $('.content');
            for (var a=0; a<els.length; a++) {
                var item = els[a];
                var el = $(item).find('.rFlag');

                if (el) {
                    if (el[0]) {
                        if (el[0].innerHTML.toString().indexOf('English') != -1) {
                            
                            var elsub = $(item).find('.rItem');
                            var subitem = elsub[1].innerHTML.toString();
                            
                            if (subitem.trim().length > 0) {
                                console.log('Subtitle found!');
                                
                                // console.log(el[0]);
                                // console.log(elsub[1]);

                                $(elsub[1]).find('button')[0].click();
                                
                                setTimeout(function(){
                                    enableRedirect = true;
                                }, 3333);

                                clearInterval(searchSubtitleInterval);
                                break;
                            }
                        }
                    }
                }
            }
        }, 1000);

        // Redirect control.
        enableRedirectInterval = setInterval(function(){
            if (enableRedirect == true) {
                enableRedirect = false;

                console.log("Redirect...");

                // Capture current URL.
                var currentUrl = getUrlParameter('videoUrl');
                currentUrl = decodeURI(currentUrl);
                console.log('Current URL: '+ currentUrl);

                // Check current URL exists in configs...
                urls = urls.trim();
                urls = urls.split("\n");
                var redirectUrl = '';

                for (var a=0; a<urls.length; a++) {
                    if (currentUrl == urls[a]) {
                        if (urls[a+1])
                            redirectUrl = urls[a+1];
                        break;
                    }
                }
                
                // Redirect.
                if (redirectUrl.length > 0) {
                    console.log('Redirect URL: '+ redirectUrl);
                    window.location.href = 'https://download.checksub.com/download?videoUrl='+ redirectUrl;
                } else {
                    console.log("\n\n\nFinished!\n\n\nLove Jesus!\n\n\n");
                }

                clearInterval(enableRedirectInterval);
            }
        }, 1000);
    });
}

var getUrlParameter = function getUrlParameter(sParam) {
    var url = window.location.href.toString().trim();
    url = decodeURI(url);
    url = url.split('videoUrl=');
    
    if (!url[1])
        return null;

    url = url[1].toString().trim();
    return url;
};

injector.js

var script = document.createElement('script');
script.setAttribute('type', 'text/javascript');
script.src = chrome.extension.getURL('injected.js');
setTimeout(function() {
	  document.head.appendChild(script);
});

manifest.json

{
    "manifest_version": 2,
    "name": "Download subtitle",
    "short_name": "DownSub",
    "version": "1.0.0",
    "content_scripts": [{
		"matches": [
			"*://*/*"
		],
        "js": [ "injector.js" ],
        "run_at": "document_start",
		"persistent": false
    }],
    "web_accessible_resources": [
        "injected.js"
    ]
}