2个有焦点时文字消失或变淡效果

有焦点时文字消失。

有焦点时文字变淡。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"/>
    <title>请输入关键字查询加强版 - 豪情</title>
    <style type="text/css">
        *{ margin:0; padding:0;}
        body{font:12px/1.5 arial;background: #fff;}
        .username{ position:relative;margin:30px auto; 500px;}
        .default{ position:absolute;top:10px;left:2px;padding:0 8px; z-index:1; color:#8B9096;cursor:text;}
        .txt{ position:relative; height:35px; padding:0 6px;border-radius:5px; line-height:35px;background: #fff; border:1px solid #9DADC5;}
    </style>
</head>
<body>
<div class="username">
    <label class="default" id="default" for="txt1">请输入关键字查询</label>
    <input type="text" name="" id="txt1" class="txt" value="" />
</div>
<script type="text/javascript">
    var oTxt = document.getElementById('txt1');
    var oDefault = document.getElementById('default');
    var sOld = oDefault.innerHTML;
    oTxt.onfocus = function(){
        oDefault.style.color = '#ccc';
    }
    oTxt.onblur = function(){
        oDefault.style.color = '#8B9096';
    }
    oTxt.onpropertychange = oTxt.oninput = toChange;
    oTxt.value.length > 0 && (oDefault.innerHTML = '');
    function toChange(){
        if(oTxt.value.length > 0){
            oDefault.innerHTML = '';
        } else {
            oDefault.innerHTML = sOld;
            bWrite = false;
        }
    }
</script>
</body>
</html>