Web TextBox水印效果实现原理

水印效果：

 

实现原理：利用文本框的焦点事件：聚焦+失焦

 

JS+CSS: 略

onfocus，onblur

 

SilverLight

 

        /// <summary>
        /// 失去焦点
        /// </summary>
        private void TextBox_LostFocus(object sender, RoutedEventArgs e)
        {
            WaterTextBox.Text = "必填！请输入...";
            WaterTextBox.Foreground = new SolidColorBrush(Colors.Gray);
        }

        //获得焦点
        private void TextBox_GotFocus(object sender, RoutedEventArgs e)
        {
            WaterTextBox.Text = "";
            WaterTextBox.Foreground = new SolidColorBrush(Colors.Magenta);
        }