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HTML

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HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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Adding Classes

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About the <head>

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Insecure Resource

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CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

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JavaScript

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Babel includes JSX processing.

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HTML
!

CSS 

              
                body {
  background: radial-gradient(hsl(200, 83%, 12%), hsl(200, 83%, 5%));
  padding: 1em;
  display: flex;
  justify-content: center;
}
div {
  box-shadow: rgba(255, 255, 255, 0.5) 0 0 5px;
  background: black;
  display: flex;
  flex-flow: wrap;
  width: 273px;
  border: solid 1px white;
  border-radius: 3px;
  padding: 2px 2px 5px;
}
p {
  color: white;
  font-size: 30px;
  width: 30px;
  height: 30px;
  text-align: center;
  margin: 0;
}
p.original {
  color: hsl(0, 80%, 40%);
}
p.valid {
  color: hsl(120, 40%, 50%);
}
p:nth-of-type(3),
p:nth-of-type(6),
p:nth-of-type(12),
p:nth-of-type(15),
p:nth-of-type(21),
p:nth-of-type(24),
p:nth-of-type(30),
p:nth-of-type(33),
p:nth-of-type(39),
p:nth-of-type(42),
p:nth-of-type(48),
p:nth-of-type(51),
p:nth-of-type(57),
p:nth-of-type(60),
p:nth-of-type(66),
p:nth-of-type(69),
p:nth-of-type(75),
p:nth-of-type(78) {
  border-right: solid 1px rgba(255, 255, 255, 0.5);
}
p:nth-of-type(19),
p:nth-of-type(20),
p:nth-of-type(21),
p:nth-of-type(22),
p:nth-of-type(23),
p:nth-of-type(24),
p:nth-of-type(25),
p:nth-of-type(26),
p:nth-of-type(27),
p:nth-of-type(46),
p:nth-of-type(47),
p:nth-of-type(48),
p:nth-of-type(49),
p:nth-of-type(50),
p:nth-of-type(51),
p:nth-of-type(52),
p:nth-of-type(53),
p:nth-of-type(54)
{
  border-bottom: solid 1px rgba(255, 255, 255, 0.5);
  padding-bottom: 4px;
}
!

JS 

              
                const sudoku = [
  8, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 3, 6, 0, 0, 0, 0, 0,
  0, 7, 0, 0, 9, 0, 2, 0, 0,
  0, 5, 0, 0, 0, 7, 0, 0, 0,
  0, 0, 0, 0, 4, 5, 7, 0, 0,
  0, 0, 0, 1, 0, 0, 0, 3, 0,
  0, 0, 1, 0, 0, 0, 0, 6, 8,
  0, 0, 8, 5, 0, 0, 0, 1, 0,
  0, 9, 0, 0, 0, 0, 4, 0, 0
]

let getLineArray = (nth, grid) => {
  // Base line index
  let b = 9 * (nth - 1)
  return [grid[b], grid[b+1], grid[b+2], grid[b+3], grid[b+4], grid[b+5], grid[b+6], grid[b+7], grid[b+8]]
}
let getColArray = (nth, grid) => {
  // Base column index
  let b = nth - 1
  return [grid[b], grid[b+9], grid[b+18], grid[b+27], grid[b+36], grid[b+45], grid[b+54], grid[b+63], grid[b+72]]
}
let squareNbToBaseIndex = (nth) => {
  let b;
  switch (nth) {
    case 1:
      b = 0;
      break;
    case 2:
      b = 3;
      break;
    case 3:
      b = 6;
      break;
    case 4:
      b = 27;
      break;
    case 5:
      b = 30;
      break;
    case 6:
      b = 33;
      break;
    case 7:
      b = 54;
      break;
    case 8:
      b = 57;
      break;
    case 9:
      b = 60;
      break;
  }
  return b
}
let getSquareArray = (nth, grid) => {
  // Base square index
  let b = squareNbToBaseIndex(nth);
  
  return [grid[b], grid[b+1], grid[b+2], grid[b+9], grid[b+9+1], grid[b+9+2], grid[b+18], grid[b+18+1], grid[b+18+2]]
  
}

let isNumberInLine = (nb, lineIndex, grid) => {
  let result = false
  let lineArray = getLineArray(lineIndex, grid)
  for (let i = 0; i < 9; i++) {
    if (lineArray[i] == nb) result = true
  }
  return result
}
let isNumberInCol = (nb, colIndex, grid) => {
  let result = false
  let colArray = getColArray(colIndex, grid)
  for (let i = 0; i < 9; i++) {
    if (colArray[i] == nb) result = true
  }
  return result
}
let isNumberInSquare = (nb, squareIndex, grid) => {
  let result = false
  let squareArray = getSquareArray(squareIndex, grid)
  for (let i = 0; i < 9; i++) {
    if (squareArray[i] == nb) result = true
  }
  return result
}

let isLineOK = (nth, grid) => {
  // Line is OK if all numbers are detected in it
  return (isNumberInLine(1, nth, grid) && isNumberInLine(2, nth, grid) && isNumberInLine(3, nth, grid) && isNumberInLine(4, nth, grid) && isNumberInLine(5, nth, grid) && isNumberInLine(6, nth, grid) && isNumberInLine(7, nth, grid) && isNumberInLine(8, nth, grid) && isNumberInLine(9, nth, grid))
}
let isColOK = (nth, grid) => {
  // Col is OK if all numbers are detected in it
  return (isNumberInCol(1, nth, grid) && isNumberInCol(2, nth, grid) && isNumberInCol(3, nth, grid) && isNumberInCol(4, nth, grid) && isNumberInCol(5, nth, grid) && isNumberInCol(6, nth, grid, grid) && isNumberInCol(7, nth, grid) && isNumberInCol(8, nth, grid) && isNumberInCol(9, nth, grid))
}
let isSquareOK = (nth, grid) => {
  // Square is OK if all numbers are detected in it
  return (isNumberInSquare(1, nth, grid) && isNumberInSquare(2, nth, grid) && isNumberInSquare(3, nth, grid) && isNumberInSquare(4, nth, grid) && isNumberInSquare(5, nth, grid) && isNumberInSquare(6, nth, grid) && isNumberInSquare(7, nth, grid) && isNumberInSquare(8, nth, grid) && isNumberInSquare(9, nth, grid))
}

let vizInit = () => {
  let body = document.getElementsByTagName('body')[0]
  let div = document.createElement('div')
  body.append(div)
  for (let i = 0; i < sudoku.length; i++) {
      let p = document.createElement("p")
      div.append(p)
  }
}

// Hahaha deep cloning dirty
let candidate = JSON.parse(JSON.stringify(sudoku))

// Memory of states (true -> keep, false -> discard)
let keeper = []
let initKeeper = () => {
  keeper = []
  for (let i = 0; i < 81; i++) {
    keeper.push(sudoku[i] !== 0 ? true : false)
  }
}
let saveKeeperLine = (nth) => {
  // Base line index
  let b = 9 * (nth - 1)
  keeper[b] = true; keeper[b+1] = true; keeper[b+2] = true; keeper[b+3] = true; keeper[b+4] = true; keeper[b+5] = true; keeper[b+6] = true; keeper[b+7] = true; keeper[b+8] = true;
}
let saveKeeperCol = (nth) => {
  // Base column index
  let b = nth - 1
  keeper[b] = true; keeper[b+9] = true; keeper[b+18] = true; keeper[b+27] = true; keeper[b+36] = true; keeper[b+45] = true; keeper[b+54] = true; keeper[b+63] = true; keeper[b+72];
}
let saveKeeperSquare = (nth) => {
  // Base square index
  let b = squareNbToBaseIndex(nth);
  
  keeper[b] = true; keeper[b+1] = true; keeper[b+2] = true; keeper[b+9] = true; keeper[b+9+1] = true; keeper[b+9+2] = true; keeper[b+18] = true; keeper[b+18+1] = true; keeper[b+18+2] = true;
}

let modelInit = () => {
  initKeeper()
}
let modelLoop = () => {
  // Change unkept numbers
  for (let i = 0; i < sudoku.length; i++) {
    if (!keeper[i]) {
      candidate[i] = Math.ceil(9 * Math.random())
    }
  }
  
  // Check validity of lines, if so tell keeper to save correponding numbers
  if (isLineOK(1, candidate)) { saveKeeperLine(1); }
  if (isLineOK(2, candidate)) { saveKeeperLine(2); }
  if (isLineOK(3, candidate)) { saveKeeperLine(3); }
  if (isLineOK(4, candidate)) { saveKeeperLine(4); }
  if (isLineOK(5, candidate)) { saveKeeperLine(5); }
  if (isLineOK(6, candidate)) { saveKeeperLine(6); }
  if (isLineOK(7, candidate)) { saveKeeperLine(7); }
  if (isLineOK(8, candidate)) { saveKeeperLine(8); }
  if (isLineOK(9, candidate)) { saveKeeperLine(9); }
  
  if (isColOK(1, candidate)) { saveKeeperCol(1); }
  if (isColOK(2, candidate)) { saveKeeperCol(2); }
  if (isColOK(3, candidate)) { saveKeeperCol(3); }
  if (isColOK(4, candidate)) { saveKeeperCol(4); }
  if (isColOK(5, candidate)) { saveKeeperCol(5); }
  if (isColOK(6, candidate)) { saveKeeperCol(6); }
  if (isColOK(7, candidate)) { saveKeeperCol(7); }
  if (isColOK(8, candidate)) { saveKeeperCol(8); }
  if (isColOK(9, candidate)) { saveKeeperCol(9); }
  
  if (isSquareOK(1, candidate)) { saveKeeperSquare(1); }
  if (isSquareOK(2, candidate)) { saveKeeperSquare(2); }
  if (isSquareOK(3, candidate)) { saveKeeperSquare(3); }
  if (isSquareOK(4, candidate)) { saveKeeperSquare(4); }
  if (isSquareOK(5, candidate)) { saveKeeperSquare(5); }
  if (isSquareOK(6, candidate)) { saveKeeperSquare(6); }
  if (isSquareOK(7, candidate)) { saveKeeperSquare(7); }
  if (isSquareOK(8, candidate)) { saveKeeperSquare(8); }
  if (isSquareOK(9, candidate)) { saveKeeperSquare(9); }
}

let vizLoop = () => {
    // Refresh
    for (let i = 0; i < sudoku.length; i++) {
      let p = document.getElementsByTagName('p')[i]
      p.innerHTML = candidate[i]
    }
    
    // Check validity and highlights
    for (let i = 0; i < sudoku.length; i++) {
      let p = document.getElementsByTagName('p')[i]
      p.className = candidate[i] == sudoku[i] ? "original" : (keeper[i] ? "valid" : "")
    }
}

modelInit()
vizInit()

setInterval(() => {
  modelLoop()
  vizLoop()
}, 50)
!
999px

Console