总结一些常用的正则表达式:用户名/^[a-z0-9_-]{3,16}$/密码 /^[a-z0-9_-]{6,18}$/电子邮箱 /^([a-z0-9_\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})$//^[a-z\d]+(\.[a-z\d]+)*@([\da-z](-[\da-z]))+(\.{1,2}[a-z]+)+$/URL/^(https