DOM实现淡出的效果

<script language="JavaScript">
var hex = 255; // 初始颜色值.

function fadetext(){
 if(hex>0) {
  hex -= 5; // 加深文字的颜色
  document.getElementById("sample").style.color="rgb("+hex+","+hex+","+hex+")";
  setTimeout("fadetext()",20);
 }
 else
  hex = 255; //　重置颜色值
}

</script>

<div >运行效果</button>