C#验证码控件（安全较高的验证码）

body { font-size: 8pt; font-family: Verdana, Arial; } input { border-right: #a7b2c3 1px solid; border-top: #a7b2c3 1px solid; border-left: #a7b2c3 1px solid; border-bottom: #a7b2c3 1px solid; font-size: 8pt; font-family: Verdana, Arial; } td { font-size: 8pt; font-family: Verdana,Arial; word-wrap: break-word; }