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，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！" >

回复讨论(解决方案)

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);	}}

getimg.php

<?phpsession_start();include './checkcode.class.php';$checkcode = new checkcode('C:\WINDOWS\Fonts\ARIAL.TTF');$checkcode->doimage();$_SESSION['code']=$checkcode->get_code();

test.php

<!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>	

submit.php

<?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