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              // Based on

// --------------------------------------------------
// Create a color palette of all 4,096 3-digit hexadecimal colors
// --------------------------------------------------

// Hexadecimal digits
var digits = ['f', 'e', 'd', 'c', 'b', 'a', '9', '8', '7', '6', '5', '4', '3', '2', '1', '0']

// Create a swatch book
var swatchBook = document.createElement('div') = 'swatchBook'

// Recurisvely create a swatch with each combination of hexadecimal digits from the array
digits.forEach(function(red) {
 digits.forEach(function(green) {
  digits.forEach(function(blue) {

   // Define a color using three hexadecimal digits
   var hexColor = '#' + red + green + blue

   // Create a swatch
   var swatch = document.createElement('div') = 'swatch' = hexColor = '100px' = '150px' = '1px' = '10px' = 'left' = 'Helvetica, Arial, sans-serif' = '1em'

   // --------------------------------------------------
   // Label each swatch
   // --------------------------------------------------

   // Get the rgb value for the background color
   var backgroundColor ="background-color")
   // Convert to an object, see function below
   var rgbColors = convertColor(backgroundColor)
   // Set text color to white or dark gray based on the brightness = (brightness(rgbColors[0], rgbColors[1], rgbColors[2]) > 123) ? '#333' : '#fff'

   // Add label = 'pre' // enable line returns
   swatch.textContent = hexColor + '\r\n'
   swatch.textContent += 'r: ' + rgbColors[0] + '\r\n'
   swatch.textContent += 'g: ' + rgbColors[1] + '\r\n'
   swatch.textContent += 'b: ' + rgbColors[2] + '\r\n'
   // swatch.textContent += 'B: ' + brightness(rgbColors[0], rgbColors[1], rgbColors[2]) + '\r\n' // display the brightness value

   // Add the swatch to the swatch book

// Display the swatch book

// --------------------------------------------------
// Get the brightness of a color
// --------------------------------------------------

// Calculate the brightness of an rgb color
function brightness(r, g, b) {
 return (r * 299 + g * 587 + b * 114) / 1000

// --------------------------------------------------
// Convert CSS rgbColor value to an array
// --------------------------------------------------

// Convert an rgb color into an object with 3 elements for r, g, and b
function convertColor(color)
  var rgbColors=new Object();

  // Handle rgb(redValue, greenValue, blueValue) format
  if (color[0]=='r')
    // Find the index of the redValue.  Using subscring function to
    // get rid off "rgb(" and ")" part.
    // The indexOf function returns the index of the "(" and ")" which we
    // then use to get inner content.
    color=color.substring(color.indexOf('(')+1, color.indexOf(')'));

    // Notice here that we don't know how many digits are in each value,
    // but we know that every value is separated by a comma.
    // So split the three values using comma as the separator.
    // The split function returns an object.
    rgbColors=color.split(',', 3);

    // Convert redValue to integer
    // Convert greenValue to integer
    // Convert blueValue to integer

  // Handle the #RRGGBB' format
  else if (color.substring(0,1)=="#")
    // This is simples because we know that every values is two
    // hexadecimal digits.
    rgbColors[0]=color.substring(1, 3);  // redValue
    rgbColors[1]=color.substring(3, 5);  // greenValue
    rgbColors[2]=color.substring(5, 7);  // blueValue

    // We need to convert the value into integers,
    // but the value is in hex (base 16)!
    // Fortunately, the parseInt function takes a second parameter
    // signifying the base we're converting from.
    rgbColors[0]=parseInt(rgbColors[0], 16);
    rgbColors[1]=parseInt(rgbColors[1], 16);
    rgbColors[2]=parseInt(rgbColors[2], 16);
  return rgbColors;
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