diff --git a/plugin/kcaptcha/kcaptcha.lib.php b/plugin/kcaptcha/kcaptcha.lib.php
index 74d9054fb..511d0352d 100644
--- a/plugin/kcaptcha/kcaptcha.lib.php
+++ b/plugin/kcaptcha/kcaptcha.lib.php
@@ -31,10 +31,10 @@ class KCAPTCHA{
 				}
 			}
 		    closedir($handle);
-		}	
-	
+		}
+
 		$alphabet_length=strlen($alphabet);
-		
+
 		do{
             /*
 			// generating random keystring
@@ -132,7 +132,7 @@ class KCAPTCHA{
 		$img2=imagecreatetruecolor($width, $height+($show_credits?12:0));
 		$foreground=imagecolorallocate($img2, $foreground_color[0], $foreground_color[1], $foreground_color[2]);
 		$background=imagecolorallocate($img2, $background_color[0], $background_color[1], $background_color[2]);
-		imagefilledrectangle($img2, 0, 0, $width-1, $height-1, $background);		
+		imagefilledrectangle($img2, 0, 0, $width-1, $height-1, $background);
 		imagefilledrectangle($img2, 0, $height, $width-1, $height+12, $foreground);
 		$credits=empty($credits)?$_SERVER['HTTP_HOST']:$credits;
 		imagestring($img2, 2, $width/2-imagefontwidth(2)*strlen($credits)/2, $height-2, $credits, $background);
@@ -203,12 +203,12 @@ class KCAPTCHA{
 				imagesetpixel($img2, $x, $y, imagecolorallocate($img2, $newred, $newgreen, $newblue));
 			}
 		}
-		
-		header('Expires: Mon, 26 Jul 1997 05:00:00 GMT'); 
-		header('Cache-Control: no-store, no-cache, must-revalidate'); 
-		header('Cache-Control: post-check=0, pre-check=0', FALSE); 
+
+		header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
+		header('Cache-Control: no-store, no-cache, must-revalidate');
+		header('Cache-Control: post-check=0, pre-check=0', FALSE);
 		header('Pragma: no-cache');
-		
+
 		if(function_exists("imagejpeg")){
 			header("Content-Type: image/jpeg");
 			imagejpeg($img2, null, $jpeg_quality);
@@ -240,10 +240,10 @@ function captcha_html($class="captcha")
     $html .= "\n".'<script src="'.G5_CAPTCHA_URL.'/kcaptcha.js"></script>';
     $html .= "\n".'<fieldset id="captcha" class="'.$class.'">';
     $html .= "\n".'<legend><label for="captcha_key">자동등록방지</label></legend>';
-    if (G5_IS_MOBILE) $html .= '<audio src="#" id="captcha_audio" controls></audio>';
+    if (is_mobile()) $html .= '<audio src="#" id="captcha_audio" controls></audio>';
     //$html .= "\n".'<img src="#" alt="" id="captcha_img">';
     $html .= "\n".'<img src="javascript:void(0);" alt="" id="captcha_img">';
-    if (!G5_IS_MOBILE) $html .= "\n".'<button type="button" id="captcha_mp3"><span></span>숫자음성듣기</button>';
+    if (!is_mobile()) $html .= "\n".'<button type="button" id="captcha_mp3"><span></span>숫자음성듣기</button>';
     $html .= "\n".'<button type="button" id="captcha_reload"><span></span>새로고침</button>';
     $html .= '<input type="text" name="captcha_key" id="captcha_key" required class="captcha_box required" size="6" maxlength="6">';
     $html .= "\n".'<span id="captcha_info">자동등록방지 숫자를 순서대로 입력하세요.</span>';