如下所示 ：
复制代码代码如下:
<! 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">
<голова>
<meta http-equiv = "content-type" content = "text /html; charset = utf-8" />
<title> 无标题文档 </title>
<стиль типа = "text/css">
.clearfieldblurred {
Цвет: #CCC;
в стиле шрифта: курсив;
шрифт-вес: нормальный;
Ширина: 150px;
}
.clearFieldActive {
Цвет:#4E4E4E;
шрифт-вес: жирный шрифт;
Ширина: 150px;
}
</style>
<script type = "text/javascript">
function clearfiled () {
var bbb = document.getElementbyId ("bbb");
if (bbb.value == "bbb") {
bbb.value = '';
bbb.classname = 'clearfieldactive';
}
}
window.document.onmousedown = function () {
var bbb = document.getElementbyId ('bbb');
if (bbb.value == "") {
bbb.value = 'bbb';
bbb.classname = 'clearfieldblurred';
}
}
</script>
</head>
<тело>
<input type = "text" id = "aaa" value = "aaa" onfocus = "if (this.value == 'aaa') {this.value = ''; this.classname = 'clearfieldactive';}" Onblur = "if (this.value == '') {this.value = 'aaa'; this.classname = 'clearfieldblurred';}"/>
<br />
<input type = "text" id = "bbb" value = "bbb" onclick = "clearfiled ()" />
</body>
</html>