<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript" language="javascript">
//得到焦点时触发事件
function onFocusFun(element, elementValue) {
if (element.value == elementValue) {
element.value = "";
element.style.color = "";
}
}
//离开输入框时触发事件
function onblurFun(element, elementValue) {
if (element.value == '') {
element.style.color = "#808080";
element.value = elementValue;
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
c#鼠标点击TextBox控件后清空值
<table cellpadding="0" cellspacing="0" width="280">
<tr>
<td colspan="2">
方法一：通过javascript
</td>
</tr>
<tr>
<td>
用户名：
</td>
<td>
<asp:TextBox ID="txt_User" runat="server" Text="请输入用户名" ForeColor="#808080" OnFocus="onFocusFun(this,'请输入用户名')" OnBlur="onblurFun(this,'请输入用户名')"></asp:TextBox>
</td>
</tr>
<tr>
<td>
密码：
</td>
<td>
<asp:TextBox ID="txt_pwd" runat="server"></asp:TextBox>
</td>
</tr>
</table>
<br />
<table width="280">
<tr>
<td colspan="2">
方法二：通过后台调用实现
</td>
</tr>
<tr>
<td>
用户名
</td>
<td>
<asp:TextBox ID="txtName" runat="server" Text="请输入用户名" ForeColor="#808080" OnFocus="onFocusFun(this,'请输入用户名')" OnBlur="onblurFun(this,'请输入用户名')"></asp:TextBox>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
protected void Page_Load(object sender, EventArgs e)
{
txtName.Attributes.Add("Value", "请输入用户名");
txtName.Attributes.Add("OnFocus", "if(this.value=='请输入用户名') {this.value=''}");
txtName.Attributes.Add("OnBlur", "if(this.value==''){this.value='请输入用户名'}");
if (!IsPostBack)
{
}
}
