会话变量在Jquery发布的脚本中不可见？

如何解决会话变量在Jquery发布的脚本中不可见？

| 我正在尝试将验证码实现为表单。 有三个文件： html表单。 PHP验证码图片生成器。 PHP验证码检查器。 Everythiong正常运行，但是我似乎无法在验证码检查器脚本上检索由验证码脚本创建的Session变量。 形式：

<img src=\"captcha/captcha.php\"></img>
<input type=\"text\" id=\"CAPTCHA\"><p id=\"caperror\"></p>
<p><input name=\"B1\" type=\"submit\" value=\"Submit\" />
</form> 

<script>
$(\'#contactform\').submit(function () {
    var cap = $(\'#CAPTCHA\').val();
    cap = \'CAPTCHA=\' + cap;
    $.ajax({
        type: \'POST\',url: \'captcha/capcheck.php\',data: cap,success: success,dataType: \"text\",error: postfail
    });
});

function success(result) {
    if (result == \'true\') {
        alert(\'Correct\');
        return true;
    } else {
        alert(result);
        return false;
    }
}

function postfail() {
    alert(\'post failed\');
    return false;
}
</script>

会话变量[\'CAPTCHA \']在captcha.php脚本中生成。 我尝试检索它，并使用以下命令在capcheck.php脚本中对其进行检查：

<?php 
session_start();  

if($SESSION[\'CAPTCHA\']) {
echo \'session=\'.$SESSION[\'CAPTCHA\'];
}
if((isset($POST[\'CAPTCHA\'])) && (isset($SESSION[\'CAPTCHA\']))){
if($_SESSION[\'CAPTCHA\'] != $_POST[\'CAPTCHA\']) {

    echo \'false\';


    } else {
    session_destroy();
        echo \'true\';
}

}
else{
echo $_POST[\'CAPTCHA\'].\'    \'. $SESSION[\'CAPTCHA\'];
session_destroy();
}
?>

它总是空的，我不知道为什么！我在没有jquery的情况下在另一个站点上实现了它，并且效果很好。 Captcha.php：

    <?php

        session_start();

        /**
         * Send PNG headers to the browser
        **/
        header(\'content-type: image/png\');

        $numbers    = array();
        $numbers[]  = rand(1,5);
        $numbers[]  = rand(1,5);

        if(rand(0,1) == 0) {
            $_op                        = \'+\'; 
            $code                       = strval($numbers[0]) .\' + \' .strval($numbers[1]) .\' =\';
            $_SESSION[\'CAPTCHA\'] = $numbers[0] + $numbers[1];
        } else {
            $_op                        = \'+\';  
            $code                       = strval($numbers[0]) .\' + \' .strval($numbers[1]) .\' =\';
            $_SESSION[\'CAPTCHA\'] = $numbers[0] + $numbers[1];
        }
        session_write_close();

        /* Our TTF font file,you may use others */
        $font = dirname(__FILE__) .\'/fonts/arial.ttf\';

        /* set the width */
        $width  = 16;
        //$width  = (strlen($code) * $width) + 2;   
        $height = 24;

        $code_length = 7;

        $image_height = $height + 2;
        $image_width  = $width * $code_length + 20;

        $im       = imagecreatetruecolor($image_width,$image_height);
        $white  = imagecolorallocate($im,255,255);
        imagefill($im,$white);

        /* Some themes */
        $theme   = array();
        $theme[]    = array(\'CHAR_COLOR\' => 
                                array(\'R\' => array(56,21),\'G\' => array(85,25),\'B\' => array(14,195) 
                                        ),\'BG_COLOR\' =>
                                array(\'R\' => array(12,76),\'G\' => array(54,67),\'B\' => array(26,23) 
                                        )
                             );
        $theme[]    = array(\'CHAR_COLOR\' => 
                                array(\'R\' => array(59,72),\'G\' => array(35,55),\'B\' => array(65,63) 
                                        ),\'BG_COLOR\' =>
                                array(\'R\' => array(30,\'G\' => array(70,30),\'B\' => array(70,30) 
                                        )
                             );
        $theme[]    = array(\'CHAR_COLOR\' => 
                                array(\'R\' => array(76,\'G\' => array(38,50),\'B\' => array(58,78) 
                                        ),\'BG_COLOR\' =>
                                array(\'R\' => array(94,\'G\' => array(97,\'B\' => array(30,55) 
                                        )
                             );

        $pos_x  = 5;
        $pos_y  = 20;
        $random = rand(0,(count($theme) - 1) );/* Get a random theme */

        /**
         *  Place each character into the image 
        **/
        $angle  = 0;
        $size      = 16;
        for($i = 0,$count = strlen($code); $i < $count; $i++) {

            $color  = imagecolorallocate($im,rand($theme[$random][\'CHAR_COLOR\'][\'R\'][0],$theme[$random][\'CHAR_COLOR\'][\'R\'][1]),rand($theme[$random][\'CHAR_COLOR\'][\'G\'][0],$theme[$random][\'CHAR_COLOR\'][\'G\'][1]),rand($theme[$random][\'CHAR_COLOR\'][\'B\'][0],$theme[$random][\'CHAR_COLOR\'][\'B\'][1])
                                                  );        

            imagettftext($im,$size,$angle,$pos_x,$pos_y,$color,$font,$code{$i});
            $pos_x  += $width + 1;

        }

        /* Finally show image */
        imagepng($im);  
        imagedestroy($im);  
    ?>

    

解决方法

        您的某些

$POST

和

$SESSION

变量缺少下划线。如您的评论中所述，这似乎是问题所在。 我建议在这种情况下，使用文本编辑器并带有对PHP适当语法突出显示的支持，这样可以很容易地识别出此类错误。