asp.net +jquery 弹出层登录效果

.selectinput{margin-bottom:10px;width:224px;height:20px;background-color:#FFF;border:1px solid;border-color:#999 #CCC #CCC #999;}
.selectinput .txt{float:left;width:165px;border:none;}
.loginpsw label{float:left;display:inline;margin:0 0 0 4px;width:50px;height:auto;line-height:150%; color:#339900}
body,td,input,textarea,select,button{color:#666;font:12px/1.6em Verdana,Helvetica,Arial,sans-serif;}
input,select,button{vertical-align:middle;}
.txt,.txtarea{padding:2px;*padding:0 2px;height:16px;*height:20px;border:1px solid;border-color:#999 #CCC #CCC #999;background:#FFF;}
body{ margin:0 auto;}
.login{border:solid 3px #339900; width:360px; height:223px;display:none; z-index:101;position:absolute; background-color:#FFFFFF;}
.login .title{width:100%;height:30px;line-height:30px; border-bottom:solid 1px #339900;}
.login .title b{ padding-left:5px; color:#000000;}
.login .pad{padding-left:35px;}
.login .divCode{width:80px; height:30px;position:relative;top: -32px;left:170px; display:none;}
.login #btnLogin{width:55px; height:28px;}
#greybackground{background:#000000;width:100%; display:block; z-index:100; top:0px; left:0px; position:absolute;}

<%@ WebHandler Language="C#" Class="login" %>

using System;
using System.Web;
using System.Web.SessionState;

public class login : IHttpHandler, IRequiresSessionState
{
    public void ProcessRequest(HttpContext context)
    {
        string code = context.Request.QueryString["code"];
        context.Response.ContentType = "text/plain";
        if (code.ToLower() != context.Session["checkCode"].ToString())
        {
            context.Response.Write("code error");
        }
        else
        {
            string name = context.Request.QueryString["name"];
            string pwd = HttpUtility.UrlDecode(context.Request.QueryString["pwd"]);
            if (name == "admin" && pwd == "admin")
            {
                context.Response.Write("success");
            }
            else
            {
                context.Response.Write("false");
            }
        }
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

}

verifyCode.ashx

<%@ WebHandler Language="C#" Class="verifyCode" %>

using System;
using System.Web;
using System.Web.SessionState;//第一步导入命名空间
using System.Drawing;

public class verifyCode : IHttpHandler, IRequiresSessionState
{//第二步实现接口 就和平常一样可以使用session

    public void ProcessRequest(HttpContext context)
    {
        string checkCode = this.CreateRandomCode(4).ToLower();
        context.Session["checkCode"] = checkCode;
        this.CreateImage(context, checkCode);
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

    ///

    ///

        //封装一个　GDI+绘图图面。无法继承此类。从指定的Image创建新的 Graphics
        Graphics g = Graphics.FromImage(image);

        //清除整个绘图面并以指定背景填充
        g.Clear(Color.AliceBlue);

        //画一个边框
        g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1);

        //定义绘制直线和曲线的对象。（只是Pen的颜色，指示此Pen的宽度的值）
        Pen blackPen = new Pen(Color.LightGray, 0);

        Random rand = new Random();

        //划横线的条数 可以根据自己的要求     

        for (int i = 0; i < 50; i++)
        {
            //随机高度
            //int y = rand.Next(image.Height);
            /*绘制一条连线由坐标对指定的两个点的线条
             线条颜色、宽度和样式，第一个点的x坐标和y坐标，第二个点的x坐标和y坐标*/
            //g.DrawLine(blackPen, 0, y, image.Width, y);
            int x = rand.Next(0, image.Width);
            int y = rand.Next(0, image.Height);
            //画矩形，坐标（x,y）宽高(1,1)
            g.DrawRectangle(blackPen, x, y, 1, 1);
        }

        //拆散字符串成单个字符数组
        char[] chars = checkCode.ToCharArray();

        //文字居中
        StringFormat format = new StringFormat(StringFormatFlags.NoClip);
        format.Alignment = StringAlignment.Center;
        format.LineAlignment = StringAlignment.Center;

        //定义颜色
        Color[] c = { Color.Black, Color.DarkGray, Color.DarkOrange, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
        //定义字体
        string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体", "Arial Baltic" };

        for (int i = 0; i < chars.Length; i++)
        {
            int cindex = rand.Next(c.Length);
            int findex = rand.Next(font.Length);

            //font　封装在特定设备上呈现特定字体所需的纹理和资源（字体，大小，字体样式）
            Font f = new System.Drawing.Font(font[findex], 16, System.Drawing.FontStyle.Bold);

            /*Brush定义用于填充图形图像（如矩形、椭圆、圆形、多边形和封闭路径）的内部对象
            SolidBrush(Color.White)初始化指定的颜色　指定画笔颜色为白色*/
            Brush b = new System.Drawing.SolidBrush(c[cindex]);

            Point dot = new Point(16, 16);

            //转动的度数
            float angle = rand.Next(-randAngle, randAngle);

            //移动光标到指定位置
            g.TranslateTransform(dot.X, dot.Y);
            g.RotateTransform(angle);
            /*在指定的位置并且用指定的Brush和Font对象绘制指定的文本字符串
           （指定的字符串，字符串的文本格式，绘制文本颜色和纹理，所绘制文本的左上角的x坐标，坐标）*/
            g.DrawString(chars[i].ToString(), f, b, 1, 1, format);
            //转回去
            g.RotateTransform(-angle);
            //移动光标指定位置
            g.TranslateTransform(2, -dot.Y);
        }
        //创建存储区为内存流
        System.IO.MemoryStream ms = new System.IO.MemoryStream();

        //将此图像以指定的格式保存到指定的流中（将其保存在内存流中，图像的格式）
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

        //清除缓冲区将流中的内容输出
        context.Response.ClearContent();

        //获取输出流的类型
        context.Response.ContentType = "image/Jpeg";

        //将二进制字符串写入HTTP输出流
        context.Response.BinaryWrite(ms.ToArray());

        g.Dispose();

        image.Dispose();
    }
}