php如何写注册登录验证码

php  /  管理员 发布于 8年前   177

authimg.php生成验证码的文件：

<? $IsLetter = false; //是否出现字母 session_start(); $Num  = $_GET["n"];  //生成验证码图片 header("Content-type: image/PNG"); $im   = imagecreate(46,20); srand((double)microtime()*1000000); $Red  = rand(0,200); $Green  = rand(0,200); $Blue  = rand(0,200); $Color  = imagecolorallocate($im, $Red, $Green, $Blue); $BackGround = imagecolorallocate($im, 255,255,255); imagefill($im,0,0,$BackGround);  if($IsLetter) {  $a = substr(md5($Num*10000000000000000),0,1);  $b = substr(md5($Num*10000000000000000),4,1);  $c = substr(md5($Num*10000000000000000),8,1);  $d = substr(md5($Num*10000000000000000),12,1); } else {  $a = substr(hexdec(md5($Num*10000000000000000)),2,1);  $b = substr(hexdec(md5($Num*10000000000000000)),3,1);  $c = substr(hexdec(md5($Num*10000000000000000)),4,1);  $d = substr(hexdec(md5($Num*10000000000000000)),5,1); }  $Authnum    = strtoupper($a.$b.$c.$d);  $_SESSION["Authnum"] = $Authnum;  imagestring($im, 5, 5, 2, $Authnum, $Color); for($i=0;$i<200;$i++)   //加入干扰象素 {     $randcolor = imagecolorallocate($im,rand(0,255),rand(0,255),rand(0,255));     imagesetpixel($im, rand()p , rand()0 , $randcolor); } imagepng($im); imagedestroy($im);?>

需要显示验证码的文件：

<?session_start();$AuthInput = $_POST["AuthInput"];$action = $_GET["action"];?><script language="javascript">function lyalert(){if( addform.AuthInput.value=="") {alert("请填写验证码");document.addform.AuthInput.focus();return false;} }</script><form name="addform" method="post" action="?action=save" id="addform" onsubmit="return lyalert()"><table width="500" border="1" cellpadding="5" cellspacing="0"><tr><td>验证码：</td><td><input name="AuthInput" type="text" id="AuthInput"  size="8" maxlength="4" /><script>document.write("<img src=\"authimg.php?n=",Math.random(),"\" />");</script></td></tr><tr><td colspan="2" align="center"><input type="submit" name="Button1" value="确定" id="Button1" /></td></tr></table><p>&nbsp;</p></form>  <?if($action=='save'){if ($_SESSION["Authnum"] != $AuthInput){?><script language="javascript">alert("验证码输入不正确");</script><? }else{ ?>  <script language="javascript"> alert("提交成功！");</script><?   } }?>

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