code.php
<?php Header("Content-type: image/gif"); /* * 初始化 */ $border = 0; //是否要边框 1要:0不要 $how = 4; //验证码位数 $w = $how*15; //图片宽度 $h = 20; //图片高度 $fontsize = 6; //字体大小 $alpha = "abcdefghjkmnpqrstuvwxyz"; //验证码内容1:字母 $number = "23456789"; //验证码内容2:数字 $randcode = ""; //验证码字符串初始化 srand((double)microtime()*1000000); //初始化随机数种子 $im = ImageCreate($w, $h); //创建验证图片 /* * 绘制基本框架 */ $bgcolor = ImageColorAllocate($im, 255, 255, 255); //设置背景颜色 ImageFill($im, 0, 0, $bgcolor); //填充背景色 if($border) { $black = ImageColorAllocate($im, 0, 0, 0); //设置边框颜色 ImageRectangle($im, 0, 0, $w-1, $h-1, $black);//绘制边框 } /* * 逐位产生随机字符 */ for($i=0; $i<$how; $i++) { $alpha_or_number = mt_rand(0, 1); //字母还是数字 $str = $alpha_or_number ? $alpha : $number; $which = mt_rand(0, strlen($str)-1); //取哪个字符 $code = substr($str, $which, 1); //取字符 $j = !$i ? 4 : $j+15; //绘字符位置 $color3 = ImageColorAllocate($im, mt_rand(0,100), mt_rand(0,100), mt_rand(0,100)); //字符随即颜色 ImageChar($im, $fontsize, $j, 3, $code, $color3); //绘字符 $randcode .= $code; //逐位加入验证码字符串 } /* * 添加干扰 */ for($i=0; $i<10; $i++)//绘背景干扰线 { $color1 = ImageColorAllocate($im, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255)); //干扰线颜色 ImageArc($im, mt_rand(-5,$w), mt_rand(-5,$h), mt_rand(20,300), mt_rand(20,200), 55, 44, $color1); //干扰线 } /* for($i=0; $i<$how*40; $i++)//绘背景干扰点 { $color2 = ImageColorAllocate($im, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255)); //干扰点颜色 ImageSetPixel($im, mt_rand(0,$w), mt_rand(0,$h), $color2); //干扰点 }*/ //把验证码字符串写入session session_start(); $_SESSION['randcode'] = $randcode; /*绘图结束*/ Imagegif($im); ImageDestroy($im); /*绘图结束*/ ?>
login.php
<?php /* * * */ session_start(); if($_POST[sub]){ //if(!empty($_POST[gd_pic])){ //判断验证码是否相同 if($_POST[gd_pic]==$_SESSION[randcode]){ echo "验证成功！"; }else{ echo "验证码错误"; } } ?> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>验证码测试</title> <script> function formSubmit(){ document.actionForm.action = "login.php"; document.actionForm.submit(); } </script> </head> <body> <form name="actionForm" action="login.php" method="POST"> 验证码：<input type="text" name="gd_pic"/><img src="code.php" onClick="this.src='code.php'"/><br> <input type="submit" name="sub" value="submit"/> <a href="javascript:formSubmit()" name="sub">发布</a> </form> </body> </html>