注意:以下代码需要打开php的gd库,修改php.in文件的配置,把已经注释掉的行之前的分号取消即可:extension=php_gd2.dll.
实例一,代码如下:
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$width = 165;
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$height = 120;
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$image = imagecreatetruecolor($width,$height);
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$bg_color = imagecolorallocate($image,255,255,255);
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$tm = imagecolorallocate($image,255,0,0);
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imagefilledrectangle($image,0,0,$width,$height,$bg_color);
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imagefill($image,0,0,$bg_color);
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header("content-type:image/png");
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imagepng($image);
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imagedestroy($image);
实例二,代码如下:validate.php
采用了session识别,稍微改进了一下目前网络上流传的php验证码,加入杂点,数字颜色随机显示,控制4位数字显示.
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<?php
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session_start();
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header("content-type: image/png");
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$im = imagecreate(44,18);
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$back = imagecolorallocate($im, 245,245,245);
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imagefill($im,0,0,$back);
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srand((double)microtime()*1000000);
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for($i=0;$i<4;$i++){
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$font = imagecolorallocate($im, rand(100,255),rand(0,100),rand(100,255));
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$authnum=rand(1,9);
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$vcodes.=$authnum;
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imagestring($im, 5, 2+$i*10, 1, $authnum, $font);
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}
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for($i=0;$i<100;$i++)
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{
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$randcolor = imagecolorallocate($im,rand(0,255),rand(0,255),rand(0,255));
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imagesetpixel($im, rand()%70 , rand()%30 , $randcolor);
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}
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imagepng($im);
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imagedestroy($im);
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$_session['vcode'] = $vcodes;
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?>
下面看完整实例,代码如下:
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<?php
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@header("content-type:text/html; charset=utf-8");
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session_start();
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?>
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=utf-8" />
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<title>php验证码示例</title>
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</head>
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<body>
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验证码:<br/>
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<iframe id="iimg" height="100" width=300 src="img.php" frameborder="0" ></iframe>
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<br/>
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<input type=button value="看不清,换一张" onclick="iimg.location.reload();">
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<br>
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<form action="validate.php" method="post">
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输入验证码:<input name="imgid" style="width:60">
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<input type="submit" value="确定">
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</form>
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</body>
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</html>
php判断用户输入的验证码是否与系统生成的一致,代码如下:
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<?php @header("content-type:text/html; charset=utf-8");
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session_start();
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$imgid_req = $_request['imgid'];
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$imgid_req = strtoupper($imgid_req);
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if (session_is_registered($imgid_req)) {
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echo "<font color=blue >通过验证!</font>";
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} else {
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echo "<font color=red >验证错误!</font>";
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}
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session_destroy();
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?>
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(责任编辑:最模板) |