一个简单的纯php验证码

<?php

  $char=array("a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z",

        "A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z",

        "0","2","3","4","5","6","7","8","9","1"  );

 

  $text=array_rand($char,5);  //随即获取字符

 

  //定义画布和颜色

  $image=imageCreate(200,60);

  $bg=imageColorAllocate($image,237,247,255);

  $rect_border=imageColorAllocate($image,255,238,251);

  $textColor=imageColorAllocate($image,142,203,241);

 

  $tstyle=array

  (

    "imageChar",

    "imageCharUp"

  );

 

  //画框和背景填充

  imageSetThickness($image,2);

  imageRectangle($image,0,0,303,103,$rect_border);

 

  //画出字符

  for($i=0;$i<count($text);$i++)

  {

    //随即获取画出文字的格式

    $textstyle=array_rand($tstyle,1); 

    if($i==0)

    {

      $tstyle[$textstyle]($image,5,40,30,$char[$text[$i]],$textColor);

    }

    else

    {

      $tstyle[$textstyle]($image,5,($i+2)*20,30,$char[$text[$i]],$textColor);

    }

  }

  header("Content-type:image/png");

  imagepng($image);

?>