$(document).ready(function () {
    $('.fa').each(function () {
        $(this).css('color', randomColor());
    });
});
		
var colors = ['00', '33', '66', '99', 'cc', 'ff'];
var rand = function () {
		return Math.floor(Math.random() * 6);
	   };
		
var randomColor = function () {
			var r = colors[rand()];
			var g = colors[rand()];
			var b = colors[rand()];
			return "#" + r + g + b;
		};

<h1 style="color:green;">
    GeeksforGeeks
</h1>
  
<h3>Pick a random color from array</h3>
  
<h3 id="pick" style="color:red;">
    Sample Text
</h3>
  
<br><br>
  
<button onclick="pickColor()">
    Click to change color
</button>
  
<script>
    // JavaScript code to pick
    // a random color from array
    function pickColor() {
          
        // Array containing colors
        var colors = [
            '#ff0000', '#00ff00', '#0000ff',
            '#ff3333', '#ffff00', '#ff6600'
        ];
          
        // selecting random color
        var random_color = colors[Math.floor(
                Math.random() * colors.length)];
          
        var x = document.getElementById('pick');
        x.style.color = random_color;
    }
</script>