Pen Settings



CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using it's URL and the proper URL extention.

+ add another resource


Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource


Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.


Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.


      <th>Population (M)</th>
      <th>GNP (B)</th>
    <tr><td>United Kingdom</td><td>64.231</td><td>2290</td></tr>




 *Functional JavaScript for crawling the Web

/*************************************************** *
 * Helper Fantion

function logs(){
	return arguments;

function nodes(sel, root){
	return (root || document).querySelectorAll(sel);

function finder(selector) {
  return function(root) {
    return nodes(selector, root);

function map(fn, iterable){
	return [], fn)

function prop(name){
	return function(object){
		return object[name];

function sequence() {
	var fns =;
	return fns.reduce(function(comp, fn) {
		return function(){
			var args =;
			return comp(fn.apply(null, args))

//隣り合う 2 つの配列要素に対して(左から右へ)同時に関数を適用
function reduce(fn, init, iterable){
	return [], fn, init)

function compose(){
	var fns =;
	return sequence.apply(null, fns.reverse());

function curry( orig_func ) {
	var ap = Array.prototype;
	var args = arguments;
	function fn() {
		ap.push.apply( fn.args, arguments );
		return fn.args.length < orig_func.length
		  ? fn
		  : orig_func.apply( this, fn.args );
	return function() {
		fn.args = args, 1 );
		return fn.apply( this, arguments );

function partial( orig_func ) {
	var aps = Array.prototype.slice,
	args = arguments, 1 );
	return function() {
		return orig_func.apply( this, args.concat( arguments ) ) );

 * 以下、main

var  rows = nodes("tbody tr");
var findCells = finder("td");
var getText = prop("textContent");

var getFirst = prop(0);
var getSecond = prop(1);
var getThird = prop(2);

 * テーブルの1行目(国名)を取得
console.log( "first-ColumnList", map(compose(findCells, getFirst, getText), rows) )

 * 途中の処理にlogsを挟んでデバッグ
console.log( "debug", map(compose(findCells, getFirst, logs, getText), rows) )

 * 人口の合計を取得
var sum = function(a, b) {
	return a + b;
var populations  =  map(compose(findCells, getSecond, getText, parseFloat), rows);
console.log("sum-populations", reduce(sum, 0, populations));

 * データをオブジェクトに変換
var asObject = function(data){
	return {
		population: parseFloat(getSecond(data)),
var getTexts = partial(map, getText); //getText関数をmap関数に部分適用して、arrayにgetTextを使えるようにする
console.log("toObject",  map(compose(findCells, getTexts, asObject), rows ))