PHP验证码在验证页面中的应用分析_PHP教程-php教程-PHP中文网

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对于一个网站来说，肯定会需要一个提供验证功能的页面。那么我们现在就需要考虑验证页面中的验证码的应用了。我们接下来将要为大家具体讲解有关一、准备一个展示并提交php验证码的页面

<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>    </SPAN><LI class=alt><SPAN>    @header("content-type:text/html; </SPAN><SPAN class=attribute><FONT color=#ff0000>charset</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>UTF</FONT></SPAN><SPAN>-8");     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    //打开session     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    session_start();     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag><STRONG><FONT color=#006699>?></FONT></STRONG></SPAN><SPAN>    </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><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 class=""><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><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> </SPAN><SPAN class=tag><STRONG><FONT color=#006699>/></FONT></STRONG></SPAN><SPAN>    </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>       </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN>PHP验证码示例</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=""><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><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><LI class=alt><SPAN>       验证码：</SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>br</SPAN><SPAN class=tag>/></SPAN></FONT></STRONG><SPAN>    </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>       </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>iframe</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>id</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"iimg"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>height</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"100"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>width</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>300</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>src</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"img.php"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>frameborder</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"0"</FONT></SPAN><SPAN> </SPAN><STRONG><FONT color=#006699><SPAN class=tag>></SPAN><SPAN class=tag></</SPAN><SPAN class=tag-name>iframe</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN>    </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>       </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>br</SPAN><SPAN class=tag>/></SPAN></FONT></STRONG><SPAN>    </SPAN></SPAN><LI class=""><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>button</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>value</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"看不清，换一张"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>onclick</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"iimg.location.reload();"</FONT></SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN>    </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>       </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>br</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN>    </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><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>"validate.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=""><SPAN>    </SPAN><LI class=alt><SPAN>           输入验证码：</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>"imgId"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>style</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"width:60"</FONT></SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN>    </SPAN></SPAN><LI class=""><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>"确定"</FONT></SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN>    </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><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=""><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><LI class=alt><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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二、以下是PHP验证码生成页面，该页面在第一页面中被调用

立即学习“PHP免费学习笔记（深入）”；

<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>    </SPAN><LI class=alt><SPAN>Header("Content-type: image/gif");     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>session_start();     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>//验证码为随机字符，以下是算法     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>$randval;     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>for($</SPAN><SPAN class=attribute><FONT color=#ff0000>i</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>0</FONT></SPAN><SPAN>;$i</SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>7</SPAN></FONT></STRONG><SPAN>;$i++){     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    $</SPAN><SPAN class=attribute><FONT color=#ff0000>randstr</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>mt_rand</FONT></SPAN><SPAN>(ord('A'),ord('Z'));     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    srand((double)microtime()*1000000);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    $</SPAN><SPAN class=attribute><FONT color=#ff0000>randv</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>mt_rand</FONT></SPAN><SPAN>(0,10);     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    if($randv%</SPAN><SPAN class=attribute><FONT color=#ff0000>2</FONT></SPAN><SPAN>==0){     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>       $</SPAN><SPAN class=attribute><FONT color=#ff0000>randval.</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>mt_rand</FONT></SPAN><SPAN>(0,10);     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    }else{     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>       $</SPAN><SPAN class=attribute><FONT color=#ff0000>randval.</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>chr</FONT></SPAN><SPAN>($randstr);     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    }     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>}     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>//注册PHP验证码到session     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>session_register($randval);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>//以下是绘制验证码图     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>height</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>50</FONT></SPAN><SPAN>;//图高     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>width</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>100</FONT></SPAN><SPAN>;//图宽     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>im</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>ImageCreateTrueColor</FONT></SPAN><SPAN>($width, $height);     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>white</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>ImageColorAllocate</FONT></SPAN><SPAN>($im, 255, 255, 255);     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>blue</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>ImageColorAllocate</FONT></SPAN><SPAN>($im, 0, 0, 64);     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>ImageFill($im, 0, 0, $white);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>srand((double)microtime()*1000000000);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>ImageLine($im, mt_rand(0,$width/3), mt_rand(0,$height/3), mt_rand($width/3,$width), mt_rand($height/3,$height), $blue);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>srand((double)microtime()*1000000);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>ImageLine($im, mt_rand($width/3,$width), mt_rand(0,$height/3), mt_rand(0,$width/3), mt_rand(0,$height/3), $blue);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>srand((double)microtime()*1000000);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>ImageString($im,16 , mt_rand(0,$width - strlen($randval) * 10), mt_rand(0,$height-12), $randval, $blue);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>ImageGIF($im);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>ImageDestroy($im);     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>/*     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>需要注意的是：为了支持以上绘图函数，我们必须在PHP载入GD2图形处理库，可修改 php.ini 文件中的     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>;</SPAN><SPAN class=attribute><FONT color=#ff0000>extension</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>php_gd2</FONT></SPAN><SPAN>.dll     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>为     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN></SPAN><SPAN class=attribute><FONT color=#ff0000>extension</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>php_gd2</FONT></SPAN><SPAN>.dll     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>即开启GD2库     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>*/     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag><STRONG><FONT color=#006699>?></FONT></STRONG></SPAN><SPAN>    </SPAN></SPAN></LI></OL>

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三、这是验证页面，提示PHP验证码是否通过验证

立即学习“PHP免费学习笔记（深入）”；

<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> @header("content-type:text/html; </SPAN><SPAN class=attribute><FONT color=#ff0000>charset</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>UTF</FONT></SPAN><SPAN>-8");     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    //开启session     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    session_start();     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    //得到用户输入的验证码，并转换成大写     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    $</SPAN><SPAN class=attribute><FONT color=#ff0000>imgId_req</FONT></SPAN><SPAN> = $_REQUEST['imgId'];     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    $</SPAN><SPAN class=attribute><FONT color=#ff0000>imgId_req</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>strtoupper</FONT></SPAN><SPAN>($imgId_req);     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    //验证该字符串是否注册了session变量     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    if (session_is_registered($imgId_req)) {     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>       echo "</SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>font</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>color</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>blue</FONT></SPAN><SPAN> </SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN>通过验证！</SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>font</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN>";     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    } else {     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>       echo "</SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>font</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>color</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>red</FONT></SPAN><SPAN> </SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN>验证错误！</SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>font</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN>";     </SPAN></SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    }     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    //关闭session，以清除所有注册过的变量     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>    session_destroy();     </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag><STRONG><FONT color=#006699>?></FONT></STRONG></SPAN><SPAN>    </SPAN></SPAN></LI></OL>

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