CodePen

HTML

            
              <a rel="191,17,27" href="#" class="color">Add values</a>

<label>
  RGB value
  <input type="text" class="color-picker-rgb" value="">
</label>

<label>
  Hex value
  <input type="text" class="color-picker-hex" value="">
</label>
            
          
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CSS

            
              body{font-family:sans-serif;}
label{display:block;}
            
          
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JS

            
              function rgbToHex(r, g, b) {
    return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
}

//put the rel values into the fields
$('.color').click(function(e) {
  e.preventDefault();  

  var rgbVal = $(this).attr('rel');

  var rgbValSplit = rgbVal.split(",");

  for (var i = 0; i < 3; i++) {
    if (!rgbValSplit[i]) {
      rgbValSplit[i] = 0;
    }
  }

  var finalHex = rgbToHex(+rgbValSplit[0], +rgbValSplit[1], +rgbValSplit[2]);

  $('.color-picker-rgb').val(rgbVal);
  $('.color-picker-hex').val(finalHex);

  $('body').css('background', finalHex);
});
            
          
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