如何运用PHP GD库生成验证码_PHP教程-php教程-PHP中文网

当我们要使用先在php.ini里增加一行引用：extension=php_gd2.dll

重启apache。做一个测试页 var_dump(gd_info());输出数据表明PHP GD库引用成功。

表单auth.html

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<OL class=dp-xml><LI class=alt><SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>html</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=""><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>head</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=alt><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>meta</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>http-equiv</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>'Content-Type'</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>content</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>'text/html; charset=utf-8'</FONT></SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN><LI class=""><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN>验证码</SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=alt><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>head</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=""><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>body</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=alt><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>h1</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN>请输入验证码</SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>h1</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=""><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>form</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>action</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"check_auth.php"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>method</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"post"</FONT></SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN><LI class=alt><SPAN>   </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>input</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>name</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"auth"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>type</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"text"</FONT></SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN><LI class=""><SPAN>   </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>img</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>src</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"auth.php"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>border</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"0"</FONT></SPAN><SPAN> </SPAN><SPAN class=tag><STRONG><FONT color=#006699>/></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN><LI class=alt><SPAN>   </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>input</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>type</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"submit"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>value</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"提交"</FONT></SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN><LI class=""><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>form</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=alt><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>body</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=""><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>html</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN></LI></OL>

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PHP GD库生成验证码 auth.php

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<OL class=dp-xml><LI class=alt><SPAN><STRONG><FONT color=#006699><SPAN class=tag><?</SPAN><SPAN class=tag-name>php</SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=""><SPAN>   session_start();  </SPAN><LI class=alt><SPAN>   header("Content-type:image/png");  </SPAN><LI class=""><SPAN> </SPAN><LI class=alt><SPAN>   $</SPAN><SPAN class=attribute><FONT color=#ff0000>img_width</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>100</FONT></SPAN><SPAN>;  </SPAN></SPAN><LI class=""><SPAN>   $</SPAN><SPAN class=attribute><FONT color=#ff0000>img_height</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>20</FONT></SPAN><SPAN>;  </SPAN></SPAN><LI class=alt><SPAN> </SPAN><LI class=""><SPAN>   srand(microtime()*100000);  </SPAN><LI class=alt><SPAN>   for($</SPAN><SPAN class=attribute><FONT color=#ff0000>i</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>0</FONT></SPAN><SPAN>;$i</SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>4</SPAN></FONT></STRONG><SPAN>;$i++)  </SPAN></SPAN><LI class=""><SPAN>   {  </SPAN><LI class=alt><SPAN>        $</SPAN><SPAN class=attribute><FONT color=#ff0000>new_number.</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>dechex</FONT></SPAN><SPAN>(rand(0,15));  </SPAN></SPAN><LI class=""><SPAN>   }  </SPAN><LI class=alt><SPAN> </SPAN><LI class=""><SPAN>   $_SESSION[check_auth]=$new_number;  </SPAN><LI class=alt><SPAN>   $</SPAN><SPAN class=attribute><FONT color=#ff0000>new_number</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>imageCreate</FONT></SPAN><SPAN>($img_width,$img_height);//创建图象  </SPAN></SPAN><LI class=""><SPAN>   ImageColorAllocate($new_number,255,255,255);  //设置背景色为白色  </SPAN><LI class=alt><SPAN> </SPAN><LI class=""><SPAN>   for($</SPAN><SPAN class=attribute><FONT color=#ff0000>i</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>0</FONT></SPAN><SPAN>;$i</SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>strlen</SPAN></FONT></STRONG><SPAN>($_SESSION[check_auth]);$i++)  </SPAN></SPAN><LI class=alt><SPAN>   {  </SPAN><LI class=""><SPAN>       $</SPAN><SPAN class=attribute><FONT color=#ff0000>font</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>mt_rand</FONT></SPAN><SPAN>(3,5);  </SPAN></SPAN><LI class=alt><SPAN>       $</SPAN><SPAN class=attribute><FONT color=#ff0000>x</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>mt_rand</FONT></SPAN><SPAN>(1,8) + $img_width*$i/4;  </SPAN></SPAN><LI class=""><SPAN>       $</SPAN><SPAN class=attribute><FONT color=#ff0000>y</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>mt_rand</FONT></SPAN><SPAN>(1,$img_height/4);  </SPAN></SPAN><LI class=alt><SPAN>       $</SPAN><SPAN class=attribute><FONT color=#ff0000>color</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>imageColorAllocate</FONT></SPAN><SPAN>($new_number,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200));//设置字符颜色  </SPAN></SPAN><LI class=""><SPAN>       imageString($new_number,$font,$x,$y,$_SESSION[check_auth][$i],$color);//输出字符  </SPAN><LI class=alt><SPAN>   }  </SPAN><LI class=""><SPAN> </SPAN><LI class=alt><SPAN>   ImagePng($new_number);  </SPAN><LI class=""><SPAN>   ImageDestroy($new_number);  </SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag><STRONG><FONT color=#006699>?></FONT></STRONG></SPAN><SPAN> </SPAN></LI></OL>

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PHP GD库提交页面 check_auth.php

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<OL class=dp-xml><LI class=alt><SPAN><STRONG><FONT color=#006699><SPAN class=tag><?</SPAN><SPAN class=tag-name>php</SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=""><SPAN>   session_start();  </SPAN><LI class=alt><SPAN>   $</SPAN><SPAN class=attribute><FONT color=#ff0000>auth</FONT></SPAN><SPAN>=$_POST['auth'];  </SPAN></SPAN><LI class=""><SPAN> </SPAN><LI class=alt><SPAN>   if(empty($auth))  </SPAN><LI class=""><SPAN>   {  </SPAN><LI class=alt><SPAN>       echo '错误：验证码不能为空';  </SPAN><LI class=""><SPAN>       die;  </SPAN><LI class=alt><SPAN>   }  </SPAN><LI class=""><SPAN> </SPAN><LI class=alt><SPAN>   if($</SPAN><SPAN class=attribute><FONT color=#ff0000>auth</FONT></SPAN><SPAN>==$_SESSION['check_auth'])  </SPAN></SPAN><LI class=""><SPAN>   {  </SPAN><LI class=alt><SPAN>       echo '正确';  </SPAN><LI class=""><SPAN>   }  </SPAN><LI class=alt><SPAN>   else  </SPAN><LI class=""><SPAN>   {  </SPAN><LI class=alt><SPAN>       echo '错误：验证码输入错误';  </SPAN><LI class=""><SPAN>   }  </SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag><STRONG><FONT color=#006699>?></FONT></STRONG></SPAN><SPAN> </SPAN></LI></OL>

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