php实例：email验证类

验证email地址的格式是否正确，代码如下：

<?php
/**
 * Email验证类
 * 根据正则验证email格式是否正确
 * N.B. 'a' in 'a_email' stands for Alberon not the pronoun!
 *
 */
class a_email
{
    /**
     * 电子邮件地址
     *
     * @var string
     */
    var $email;

    /**
     * 错误消息
     *
     * @var string
     */
    var $error_html;

    /**
     * 构造函数
     *
     * @param string $email
     * @return null
     */
    function a_email($email)
    {
        $this->email = $email;
    }

    /**
    * 验证email格式
    */
    function email_is_valid()
    {
        $valid = true;
        if (!eregi("^[_a-z0-9-]+(.[_a-z0-9-]+)*@[a-z0-9-]+(.[a-z0-9-]+)*(.[a-z]{2,8})$", $this->email))
        {
            $valid = false;
            $this->error_html = "$this->email is not properly formatted";
        }
        return $valid;
    }
}

//调用示例
$tmp_mail = "test123@jb200.com"
$email = new a_email();
if ($email->email_is_valid()){
   echo "email格式正确";
}else{
   echo "对不起，您输入的email有误.";
}