JavaScript 刷新验证码失败

JavaScript020

JavaScript 刷新验证码失败,第1张

估计是有JS的代码错误导致部分JS功能无法正常使用了，建议你在浏览器访问时按F12出来控制台查看下是否有错误的JS提示。

目测出问题的地方有两处：

1、onload="btn.disable=false"

2、document.getElementById("btn").isDisable=true

把这两个代码删掉试试。

（1）jsp代码：

<img id = "img_authcode" src="${ctx}/account/authcode" /><a href="javascript:" onclick="javascript:document.getElementById('img_authcode').setAttribute('src', '${ctx}/account/authcode?' + Math.random())">换一换</a>

（2）java代码（该代码为我自己框架代码，跟servlet写法不一样的我都给你注释了）：

public View authcode() throws IOException {

HttpServletResponse response = PuffContext.getResponse()//获取response

response.setContentType("image/jpeg")

response.setHeader("Pragma", "No-cache")

response.setHeader("Cache-Control", "no-cache")

response.setDateHeader("Expires", 0)

String authCode = AuthCodeUtil.getRandom(4)//获取验证码，代码在下面(3)

System.out.println("生成随机码：" + authCode)

PuffContext.getSession().setAttribute("session_authcode", authCode)//把该验证码存储在session

ServletOutputStream output = response.getOutputStream()

AuthCodeUtil.draw(output, authCode)

output.flush()

output.close()

return ViewFactory.nullView()//返回null

}

(3)///////////////////////////下面为生成验证码类////////////////////////////////////

public class AuthCodeUtil {

private final static Random random = new Random()

// 随机字体样式

private final static int[] fontStyle = { Font.HANGING_BASELINE, Font.ITALIC, Font.LAYOUT_LEFT_TO_RIGHT, Font.LAYOUT_NO_LIMIT_CONTEXT,

Font.LAYOUT_NO_START_CONTEXT, Font.LAYOUT_RIGHT_TO_LEFT }

/**

* 画随机码图

*

* @param out

* @param width

* @param height

* @throws IOException

*/

public static void draw(OutputStream out, String value) throws IOException {

int width = 80, height = 30

BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB)

Graphics2D g = (Graphics2D) bi.getGraphics()

g.setColor(Color.WHITE)

g.fillRect(0, 0, width, height)

g.drawRect(1, 1, width - 2, height - 2)

for (int i = 0i <10i++) {

g.setColor(randColor(150, 250))

g.drawOval(random.nextInt(110), random.nextInt(24), 5 + random.nextInt(10), 5 + random.nextInt(10))

}

int n = (int) (Math.random() * 6)

Font mFont = new Font("Arial", fontStyle[n], 23)

g.setFont(mFont)

g.setColor(randColor(10, 240))

g.drawString(value, 10, 21)// 随机数,水平距离,垂直距离

ImageIO.write(bi, "png", out)

}

private static Color randColor(int fc, int bc) {// 给定范围获得随机颜色

if (fc >255)

fc = 255

if (bc >255)

bc = 255

int r = fc + random.nextInt(bc - fc)

int g = fc + random.nextInt(bc - fc)

int b = fc + random.nextInt(bc - fc)

return new Color(r, g, b)

}

public static void main(String[] args) throws IOException {

FileOutputStream out = new FileOutputStream("d:\\aa.png")

draw(out, getRandom(4))

}

public static String getRandom(int size) {// 随机字符串

char[] c = { '1', '3', '5', '6', '7', '8', '9' }

StringBuffer sb = new StringBuffer()

for (int i = 0i <sizei++)

sb.append(c[Math.abs(random.nextInt()) % c.length])

return sb.toString()

}

}

用JavaScript来做

一般情况下验证码生成于一个Servlet，直接在<img>标签中SRC一下地址就可以,所以我们可以用动态改变地址的方式来重新刷新验证码

<script language=\"JavaScript\">

function reloadImage(url)

{

document.formName.img1.src = url

}

</script>

<img name=\"img1\" src=\"http://xxx\"><a href=\"JavaScript:reloadImage(\'http://xxx\')\">刷新</a>