前端:
<form action="pd" method="post">
<input type="text" name="cod" />
<img onclick="this.src='{:captcha_src()}?'+Math.random()" src="{:captcha_src()}" />
</form>
控制器:
if(!captcha_check($captcha)){
echo "<script>alert('验证码错误');window.history.back();</script>";
exit();
};
