Get background color of input range position - Javascript Canvas

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Description

Get background color of input range position

Demo Code

ResultView the demo in separate window 

<html>
   <head> 
      <meta name="viewport" content="width=device-width, initial-scale=1"> 
      <script type="text/javascript" src="https://code.jquery.com/jquery-1.9.1.js"></script> 
      <style id="compiled-css" type="text/css">

#canvas{border:1px solid red;}
#myRange{width:300px;}


      </style> 
      <script type="text/javascript">
    $(window).load(function(){/*from   w  w w . j  a  v a  2s .  co m*/
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.font = "14px verdana";
var $canvas = $("#canvas");
var canvasOffset = $canvas.offset();
var offsetX = canvasOffset.left;
var offsetY = canvasOffset.top;
var x1 = 0;
var y1 = 10;
var x2 = canvas.width;
var y2 = 10;
// create a gradient
var gradient = ctx.createLinearGradient(x1, y1, x2, y2);
gradient.addColorStop(0.00, "indigo");
gradient.addColorStop(1.00, "steelblue");

ctx.fillStyle = gradient;
ctx.fillRect(x1, y1 - 10, x2 - x1, 20);

var data = ctx.getImageData(x1, y1, canvas.width, 1).data;

$("#myRange").on("input change", function () {
    var value = $(this).val();
    var i = value * 4;
    var r = data[i];
    var g = data[i + 1];
    var b = data[i + 2];
    var a = data[i + 3];

    var fill = "rgba(" + r + "," + g + "," + b + "," + a + ")";
    ctx.fillStyle = fill;
    ctx.clearRect(0, 20, canvas.width, 30);
    ctx.fillRect(0, 25, 50, 20);
    ctx.fillText(fill, 75, 40);
});
    });

      </script> 
   </head> 
   <body> 
      <input id="myRange" type="range" min="0" max="299"> 
      <br> 
      <canvas id="canvas" width="300" height="45"></canvas>  
   </body>
</html>

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