<span id=blinker style="font-family:arial,helvetica;font-weight:bold">Hello World </span>
<script>
 var color = new Array
     color[0] =  "#000000"
     color[1] =  "#ff0000"
     color[2] =  "#ffff00"
     
 var index=0
 function blink()
  {
  blinker.style.color = color[index++]
  if (index == color.length)
    { 
    index=0
    blink()
    }
  else
    setTimeout("blink()",50)  
  }
 blink()
</script>