Efeito Gradiente HTMLJava

<div id="gradienttext"></div>
<script type="text/javascript">
   function toHex(value)
   {
      var hex = "0123465789ABCDEF";
      var result = hex.charAt(Math.floor(value / 16));
      result += hex.charAt(value % 16);
      return result;
   }
   var colorBegin = "#0000C8";
   var colorEnd = "#00C800";
   var text = "WYSIWYG Web Builder is awesome!";
   var r = parseInt(colorBegin.substring(1,3),16);
   var g = parseInt(colorBegin.substring(3,5),16);
   var b = parseInt(colorBegin.substring(5,7),16);
   var rr = parseInt(colorEnd.substring(1,3),16);
   var gg = parseInt(colorEnd.substring(3,5),16);
   var bb = parseInt(colorEnd.substring(5,7),16);
   var r_step = (rr - r) / text.length;
   var g_step = (gg - g) / text.length;
   var b_step = (bb - b) / text.length;
   var html = "";
   for (var x = 0; x <= text.length; x++)
   {
      html = html + '<span style="color:#' + toHex(r) + toHex(g) + toHex(b) + '";">' + text.charAt(x) + '</span>';
      r += r_step;
      g += g_step;
      b += b_step;
   }
   document.getElementById("gradienttext").innerHTML = html;
</script>