<img src="code.png" onclick="this.src ={$maccms.path_tpl}picture/captcha.png"
<script language="JavaScript">function reloadcode(){
var verify=document.getElementById('safecode')
verify.setAttribute('src','images/chknumber.jsp?'+Math.random())
//这里必须加入随机数不然地址相同我发重新加载
}
</script>
=========================
然后再验证码图片里面写onclick呼出上面的函数重新加载.
程序代码
<img src="images/chknumber.jsp"id="safecode" border="0" onclick="reloadcode()" style="cursor:handpadding:2px 8px 0pt 3px" />
js代码//**********获取验证码图片*********************************************************//
function getcodeimg()
{
var num = Math.ceil(Math.random()*100)
document.getElementById("codeimg").src = "VerifyCode.aspx?Num="+num
}
这里codeimg是网页上验证码图片的id。如下：
<img id="codeimg" alt="看不清楚请点击图片！" src="VerifyCode.aspx" onclick="getcodeimg()"/>
//*********************************************************************************//
建立一个单独生成验证码aspx页面，后台代码如下：
using System
using System.Collections
using System.ComponentModel
using System.Data
using System.Web
using System.Web.SessionState
using System.Web.UI
using System.Web.UI.WebControls
using System.Web.UI.HtmlControls
using System.Drawing
using System.Drawing.Imaging
using System.Drawing.Text
/// <summary>
/// 页面验证码程序
/// 使用：在页面中加入HTML代码 <img src="VerifyCode.aspx">
/// </summary>
public partial class VerifyCode : System.Web.UI.Page
{
static string[] FontItems = new string[] { "Arial",
"Helvetica",
"Geneva",
"sans-serif",
"Verdana"
}
static Brush[] BrushItems = new Brush[] { Brushes.OliveDrab,
Brushes.ForestGreen,
Brushes.DarkCyan,
Brushes.LightSlateGray,
Brushes.RoyalBlue,
Brushes.SlateBlue,
Brushes.DarkViolet,
Brushes.MediumVioletRed,
Brushes.IndianRed,
Brushes.Firebrick,
Brushes.Chocolate,
Brushes.Peru,
Brushes.Goldenrod
}
static string[] BrushName = new string[] {"OliveDrab",
"ForestGreen",
"DarkCyan",
"LightSlateGray",
"RoyalBlue",
"SlateBlue",
"DarkViolet",
"MediumVioletRed",
"IndianRed",
"Firebrick",
"Chocolate",
"Peru",
"Goldenrod"
}
private static Color BackColor= Color.White
private static Pen BorderColor = Pens.DarkGray
private static int Width= 58
private static int Height = 25
private Random _random
private string _code
private int_brushNameIndex
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
//InitializeComponent()
//base.OnInit(e)
}
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
//this.Load += new System.EventHandler(this.Page_Load)
}
/// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
public void Page_Load(object sender, System.EventArgs e)
{
if (!IsPostBack)
{
//
// TODO : initialize
//
this._random = new Random()
this._code = GetRandomCode()
//
// TODO : use Session["code"] save the VerifyCode
//
Session["code"] = this._code
//
// TODO : output Image
//
this.SetPageNoCache()
this.OnPaint()
}
}
/// <summary>
/// 设置页面不被缓存
/// </summary>
private void SetPageNoCache()
{
Response.Buffer = true
Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1)
Response.Expires = 0
Response.CacheControl = "no-cache"
Response.AppendHeader("Pragma","No-Cache")
}
/// <summary>
/// 取得一个 4 位的随机码
/// </summary>
/// <returns></returns>
private string GetRandomCode()
{
return Guid.NewGuid().ToString().Substring(0, 4)
}
/// <summary>
/// 随机取一个字体
/// </summary>
/// <returns></returns>
private Font GetFont()
{
int fontIndex = _random.Next(0, FontItems.Length)
FontStyle fontStyle = GetFontStyle(_random.Next(0, 2))
return new Font(FontItems[fontIndex], 12, fontStyle)
}
/// <summary>
/// 取一个字体的样式
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
private FontStyle GetFontStyle(int index)
{
switch (index)
{
case 0:
return FontStyle.Bold
case 1:
return FontStyle.Italic
default:
return FontStyle.Regular
}
}
/// <summary>
/// 随机取一个笔刷
/// </summary>
/// <returns></returns>
private Brush GetBrush()
{
int brushIndex = _random.Next(0, BrushItems.Length)
_brushNameIndex = brushIndex
return BrushItems[brushIndex]
}
/// <summary>
/// 绘画事件
/// </summary>
private void OnPaint()
{
Bitmap objBitmap = null
Graphics g = null
try
{
objBitmap = new Bitmap(Width, Height)
g = Graphics.FromImage(objBitmap)
Paint_Background(g)
Paint_Text(g)
Paint_TextStain(objBitmap)
Paint_Border(g)
objBitmap.Save(Response.OutputStream, ImageFormat.Gif)
Response.ContentType = "image/gif"
}
catch{}
finally
{
if (null != objBitmap)
objBitmap.Dispose()
if (null != g)
g.Dispose()
}
}
/// <summary>
/// 绘画背景颜色
/// </summary>
/// <param name="g"></param>
private void Paint_Background(Graphics g)
{
g.Clear(BackColor)
}
/// <summary>
/// 绘画边框
/// </summary>
/// <param name="g"></param>
private void Paint_Border(Graphics g)
{
g.DrawRectangle(BorderColor, 0, 0, Width - 1, Height - 1)
}
/// <summary>
/// 绘画文字
/// </summary>
/// <param name="g"></param>
private void Paint_Text(Graphics g)
{
g.DrawString(_code, GetFont(), GetBrush(), 3, 1)
}
/// <summary>
/// 绘画文字噪音点
/// </summary>
/// <param name="g"></param>
private void Paint_TextStain(Bitmap b)
{
for (int n=0n<30n++)
{
int x = _random.Next(Width)
int y = _random.Next(Height)
b.SetPixel(x, y, Color.FromName(BrushName[_brushNameIndex]))
}
}
}
