Greasemonkey script for send content to backend localhost.

send-to-download.js

// ==UserScript==
// @name        Post test
// @namespace   jinzhou
// @description Post Test
// @include     *
// @version     1
// @require       http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js
// @grant       GM_xmlhttpRequest
// @grant       GM_addStyle
// ==/UserScript==

// CSS
GM_addStyle("#extractor-overlay { visibility: hidden; position: fixed; left: 0px; top: 0px; width:100%; height:100%; text-align:center; z-index: 1000; background: #333} #extractor-overlay > div { width:600px; margin: 100px auto; background-color: #fff; border:1px solid #000; padding:15px; text-align:center; } #extractor-content {width: 100%; min-height:350px}");

function newSendDialog(id) {
    var dialog = document.createElement('div');
    dialog.setAttribute('id', id);
    dialog.innerHTML = '<div><p id="extractor-message"></p><textarea id="extractor-content"></textarea><div><button type="button" id="extractor-send">Send</button><button type="button" id="extractor-cancle">Cancle</button></div></div>';
    return dialog;
}

function toggleVisible(id) {
    var el = document.getElementById(id);
    el.style.visibility = (el.style.visibility === 'visible') ? 'hidden' : 'visible';
}

function sendContent(content) {
    GM_xmlhttpRequest({
            method: "POST",
            url: "http://localhost:8000",
            data: "content="+content,
            headers: {
                "Content-Type": "application/x-www-form-urlencoded"
            }
    });
}

var dialog_id = 'extractor-overlay';
var dialog = newSendDialog(dialog_id);
document.body.appendChild(dialog);


var cancleButton = document.getElementById('extractor-cancle');
cancleButton.onclick = function() {toggleVisible(dialog_id);};

// send button
var sendButton = document.getElementById('extractor-send');
sendButton.onclick = function() {
    var contentArea = document.getElementById('extractor-content');
    var extractorMsg = document.getElementById('extractor-message');
    if (contentArea.value !== null && contentArea.value !== "") {
        sendContent(contentArea.value);
        extractorMsg.innerHTML = "Send Done!";
    } else {
        extractorMsg.innerHTML = "Content empty, not send!";
    }

    toggleVisible(dialog_id);
};





var toggleButton = newToggleButton();
toggleButton.onclick = function(){
    setDefaultContent();
    toggleVisible(dialog_id);
};

appendToggleButton(toggleButton);

// Now customize two parts!
// 1. insert the toggle button to where it belongs according to the url.

function newToggleButton() {
    var url = window.location.href;
    var ret = null;
    if (url.match('www.bilibili.com/video/')) {
        ret = document.createElement('a');
        ret.className = 'i-link ret';
        ret.innerHTML = '下载';
    }

    return ret;
}

function appendToggleButton(btn) {
    var url = window.location.href;
    if (url.match('www.bilibili.com/video/')) {

        var target = document.getElementById('i_menu_login_reg');
        target.appendChild(btn);
    }
}

// 2. change the function for setting default content according to the url.
function setDefaultContent() {
    var contentArea = document.getElementById('extractor-content');
    if (contentArea.value === null || contentArea.value === "") {
        contentArea.value = window.location.href;
    }
}