diff --git a/nurikabe.coffee b/nurikabe.coffee
new file mode 100644
index 0000000..48d903a
--- /dev/null
+++ b/nurikabe.coffee
@@ -0,0 +1,153 @@
+window.Nurikabe = class Nurikabe
+  constructor: (@board) ->
+    @grid = document.createElement 'div'
+    @grid.classList.add 'game-container'
+    @board.appendChild @grid
+
+    buttons_div = document.createElement 'div'
+    buttons = {check: 'Check', reset: 'Reset', newgame: 'New game', help: '?'}
+
+    for k,v of buttons
+      button = document.createElement 'button'
+      button.innerHTML = v
+      button.classList.add k
+
+      buttons_div.appendChild button
+
+    @board.appendChild buttons_div
+
+    @board.querySelector('.check').addEventListener('click', @check.bind(this))
+    @board.querySelector('.reset').addEventListener('click', @reset.bind(this))
+
+  check: ->
+    errors = @errors()
+
+    if errors.length == 0
+      alert 'Congratulations!'
+    else
+      alert errors.map((el) -> el.message).join()
+
+  errors: ->
+    solution = @toArray()
+    errors = []
+    processed_cells = []
+    black_stream = new Stream(solution)
+    white_walls = []
+
+    for i in [0...solution.length]
+      row = solution[i]
+      for j in [0...row.length]
+        cell = solution[i][j]
+
+        if cell < 0
+          if black_stream.empty()
+            black_stream.calculate({x: i, y: j})
+          else if !black_stream.include({x: i, y: j})
+            errors.push {row: i, column: j, message: 'The stream must be continuous'}
+        else if cell > 0
+          if white_walls.some((wall) -> wall.include({x: i, y: j}))
+            errors.push {row: i, column: j, message: 'Each wall must contain exactly one numbered cell.'}
+          else
+            wall = new Stream(solution)
+            wall.calculate({x: i, y: j})
+
+            if wall.length() != cell
+              errors.push {row: i, column: j, message: 'Each numbered cell is a wall cell, the number in it is the number of cells in that wall.'}
+
+            white_walls.push(wall)
+
+    errors
+
+  generate: (game, solution = false) ->
+    @game = game if game?
+    @grid.innerHTML = @game.map((row) ->
+      '<div class="grid-row">' + row.map((cell) ->
+        if cell <= 0
+          color_class = 'black' if solution && cell == -1
+          "<div class=\"grid-cell empty #{color_class}\">&nbsp;</div>"
+        else
+          "<div class=\"grid-cell white\">#{cell}</div>"
+      ).join('') + '</div>'
+    ).join('')
+
+    for cell in board.querySelectorAll('.empty')
+      cell.addEventListener 'click', ((evenment) => @toggle evenment.target), false
+
+    return
+
+  reset: ->
+    @generate()
+
+  toggle: (cell) ->
+    if cell.classList.contains 'black'
+      cell.classList.remove 'black'
+      cell.classList.add 'white'
+    else if cell.classList.contains 'white'
+      cell.classList.remove 'white'
+    else
+      cell.classList.add 'black'
+
+  toArray: ->
+    [].map.call @grid.querySelectorAll('.grid-row'), (row) ->
+      [].map.call row.querySelectorAll('.grid-cell'), (cell) ->
+        if cell.classList.contains('empty')
+          if cell.classList.contains('black')
+            -1
+          else
+            0
+        else
+          parseInt(cell.innerHTML)
+
+class Stream
+  constructor: (@game) ->
+    @cells = []
+
+  calculate: (cell) ->
+    value = @game[cell.x][cell.y]
+    @cells = []
+    @type = if value < 0 then 'black' else 'white'
+
+    cell = {x: cell.x, y: cell.y, value: value}
+    cells_to_process = [cell]
+
+    while cells_to_process.length > 0
+      cell = cells_to_process.pop()
+      cells_to_process = cells_to_process.concat @process(cell) unless @include(cell)
+
+
+    @cells
+
+  checkCell: (cell, value) ->
+    0 <= cell.x < @game.length && 0 <= cell.y < @game[cell.x].length &&
+      (value < 0 && @game[cell.x][cell.y] < 0 || value >= 0 && @game[cell.x][cell.y] >= 0)
+
+  empty: ->
+    @cells.length == 0
+
+  getCell: (cell, value) ->
+    {x: cell.x, y: cell.y, value: @game[cell.x][cell.y]} if @checkCell(cell, value)
+
+  include: (cell) ->
+    @cells.indexOf("#{cell.x};#{cell.y}") >= 0
+
+  length: ->
+    @cells.length
+
+  process: (cell) ->
+    @cells.push("#{cell.x};#{cell.y}")
+
+    x = cell.x
+    y = cell.y
+    value = cell.value
+
+    cells_to_add = []
+    tmp_cell = @getCell({x: x+1, y: y}, value)
+    cells_to_add.push tmp_cell if tmp_cell?
+    tmp_cell = @getCell({x: x-1, y: y}, value)
+    cells_to_add.push tmp_cell if tmp_cell?
+    tmp_cell = @getCell({x: x, y: y+1}, value)
+    cells_to_add.push tmp_cell if tmp_cell?
+    tmp_cell = @getCell({x: x, y: y-1}, value)
+    cells_to_add.push tmp_cell if tmp_cell?
+
+    cells_to_add
diff --git a/nurikabe.html b/nurikabe.html
new file mode 100644
index 0000000..7389c8d
--- /dev/null
+++ b/nurikabe.html
@@ -0,0 +1,69 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Nurikabe</title>
+    <meta charset="utf-8">
+    <meta name="viewport" content="initial-scale=1.0, user-scalable=yes" />
+    <style>
+body {
+  background-color: #aaa;
+  font-family: Verdana,Arial,sans-serif;
+}
+.game-container {
+  cursor: default;
+  font-weight: bold;
+  -webkit-touch-callout: none;
+  -webkit-user-select: none;
+  -khtml-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
+  user-select: none;
+}
+.grid-cell {
+  background-color: #ddd;
+  width: 30px;
+  height: 30px;
+  display: inline-block;
+  margin: 1px;
+  padding: 5px;
+  border-radius: 3px;
+  text-align: center;
+  line-height: 30px;
+  font-size: 1.2em;
+}
+
+table {
+  border-collapse: collapse;
+}
+td {
+  border: 1px solid black;
+  height: 20px;
+  width: 20px;
+  text-align: center;
+}
+.white {
+  background-color: #fff;
+}
+.black {
+  background-color: #aaa;
+}
+    </style>
+    <script type="text/javascript" src="nurikabe.js"></script>
+    <script type="text/javascript">
+var nurikabe;
+  var game = JSON.parse("[[4,-1,-1,0,2],[0,-1,2,-1,-1],[0,-1,0,-1,3],[0,-1,-1,-1,0],[-1,-1,1,-1,0]]");
+document.addEventListener("DOMContentLoaded", function() {
+  var board = document.getElementById('board');
+
+  nurikabe = new Nurikabe(board);
+  nurikabe.generate(game);
+});
+    </script>
+  </head>
+  <body>
+    <h1>Nurikabe</h1>
+
+    <div id="board">
+    </div>
+  </body>
+</html>