PHP 输出session 验证码与图片不同步，图片总是快一步，求解！
<?session_start();function random($len){$srcstr="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";mt_srand();$strs="";for($i=0;$i<$len;$i++){$strs.=$srcstr[mt_rand(0,35)];}return strtoupper($strs);}$str=random(4); $width = 50; $height = 25; @header("Content-Type:image/png");$_SESSION["captcha"] = $str;//echo $str;$im=imagecreate($width,$height);$back=imagecolorallocate($im,0xFF,0xFF,0xFF);$pix=imagecolorallocate($im,187,230,247);$font=imagecolorallocate($im,41,163,238);mt_srand();for($i=0;$i<1000;$i++){imagesetpixel($im,mt_rand(0,$width),mt_rand(0,$height),$pix);}imagestring($im, 5, 7, 5,$str, $font);imagerectangle($im,0,0,$width-1,$height-1,$font);imagepng($im);imagedestroy($im);$_SESSION["captcha"] = $str;?><img src="captcha.php" style="max-width:90%" style="max-width:90%" border="1" onclick= "this.src='captcha.php?act=captcha&'+Math.random()" style="cursor: pointer; vertical-align:middle" title="看不清？点击更换！" / alt="PHP 输出session 验证码与图片不同步，图片总是快一步，求解！" >
PHP 输出session 验证码与图片不同步，图片总是快一步
这是什么意思？
你的代码中为什么要对$_SESSION["captcha"]重复赋值？
PHP 输出session 验证码与图片不同步，图片总是快一步
这是什么意思？
你的代码中为什么要对$_SESSION["captcha"]重复赋值？
去掉还是一样的 图片还是比 echo 快一步
这个问题很诡异，最好的方法就是分开。
试试这个吧
checkcode.class.php
<?php/** * 生成验证码 * 类用法 * $checkcode = new checkcode(); * $checkcode->doimage(); * //取得验证 * $_SESSION['code']=$checkcode->get_code(); session_start(); include './checkcode.class.php'; $checkcode = new checkcode('C:\WINDOWS\Fonts\ARIAL.TTF'); $checkcode->doimage(); $_SESSION['code']=$checkcode->get_code(); */class checkcode { //验证码的宽度 public $width=130; //验证码的高 public $height=50; //设置字体的地址 private $font; //设置字体色 public $font_color; //设置随机生成因子 public $charset = 'abcdefghkmnprstuvwyzABCDEFGHKLMNPRSTUVWYZ23456789'; //设置背景色 public $background = '#EDF7FF'; //生成验证码字符数 public $code_len = 4; //字体大小 public $font_size = 20; //验证码 private $code; //图片内存 private $img; //文字X轴开始的地方 private $x_start; function __construct($fontpath) { $this->font =$fontpath; } /** * 生成随机验证码。 */ protected function creat_code() { $code = ''; $charset_len = strlen($this->charset)-1; for ($i=0; $i<$this->code_len; $i++) { $code .= $this->charset[rand(1, $charset_len)]; } $this->code = $code; } /** * 获取验证码 */ public function get_code() { return strtolower($this->code); } /** * 生成图片 */ public function doimage() { $code = $this->creat_code(); $this->img = imagecreatetruecolor($this->width, $this->height); if (!$this->font_color) { $this->font_color = imagecolorallocate($this->img, rand(0,156), rand(0,156), rand(0,156)); } else { $this->font_color = imagecolorallocate($this->img, hexdec(substr($this->font_color, 1,2)), hexdec(substr($this->font_color, 3,2)), hexdec(substr($this->font_color, 5,2))); } //设置背景色 $background = imagecolorallocate($this->img,hexdec(substr($this->background, 1,2)),hexdec(substr($this->background, 3,2)),hexdec(substr($this->background, 5,2))); //画一个柜形，设置背景颜色。 imagefilledrectangle($this->img,0, $this->height, $this->width, 0, $background); $this->creat_font(); $this->creat_line(); $this->output(); } /** * 生成文字 */ private function creat_font() { $x = $this->width/$this->code_len; for ($i=0; $i<$this->code_len; $i++) { imagettftext($this->img, $this->font_size, rand(-30,30), $x*$i+rand(0,5), $this->height/1.4, $this->font_color, $this->font, $this->code[$i]); if($i==0)$this->x_start=$x*$i+5; } } /** * 画线 */ private function creat_line() { imagesetthickness($this->img, 3); $xpos = ($this->font_size * 2) + rand(-5, 5); $width = $this->width / 2.66 + rand(3, 10); $height = $this->font_size * 2.14; if ( rand(0,100) % 2 == 0 ) { $start = rand(0,66); $ypos = $this->height / 2 - rand(10, 30); $xpos += rand(5, 15); } else { $start = rand(180, 246); $ypos = $this->height / 2 + rand(10, 30); } $end = $start + rand(75, 110); imagearc($this->img, $xpos, $ypos, $width, $height, $start, $end, $this->font_color); if ( rand(1,75) % 2 == 0 ) { $start = rand(45, 111); $ypos = $this->height / 2 - rand(10, 30); $xpos += rand(5, 15); } else { $start = rand(200, 250); $ypos = $this->height / 2 + rand(10, 30); } $end = $start + rand(75, 100); imagearc($this->img, $this->width * .75, $ypos, $width, $height, $start, $end, $this->font_color); } /** * 输出图片 */ private function output() { header("content-type:image/png\r\n"); imagepng($this->img); imagedestroy($this->img); }}<?phpsession_start();include './checkcode.class.php';$checkcode = new checkcode('C:\WINDOWS\Fonts\ARIAL.TTF');$checkcode->doimage();$_SESSION['code']=$checkcode->get_code();<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" /></head><body > <form action="submit.php" method="post" name="myform"> <img id='code_img' onclick='this.src=this.src+"&"+Math.random()' src='getimg.php'/ alt="PHP 输出session 验证码与图片不同步，图片总是快一步，求解！" > <input name="code" type="text" class="ipt ipt_reg" /> <input name="submit" value="提交" type="submit"/> </form></body></html>
<?phpsession_start();var_dump($_SESSION);echo "<HR/>";var_dump($_REQUEST);
当然
A.php输出
浏览器请求A.php,输出了SESSION
接着渲染A页面的时候，发现图片节点，接着请求captcha.php，服务器端接着产生验证图片，这时候又产生了新的SESSION值
看来还是得好好学习
是不是浏览器安装了调试插件的问题，使浏览器会加载页面两次
是不是浏览器安装了调试插件的问题，使浏览器会加载页面两次,所以验证码也加载了两次
