JavaScript匹配邮箱

<script type="text/javascript">    //[e-mail]    //[e-mail]    //[e-mail]    var reg = /^\w[a-zA-Z0-9_\.]{4,9}@\w+(\.[a-z]+)+$/;    var str = "[e-mail]";    //结果：["[e-mail]", ".com", index: 0, input: "[e-mail]"]    var str = "sdasdasd";    //结果：null    var str = "[e-mail]";    //结果：["[e-mail]", ".com", index: 0, input: "[e-mail]"]    var res = str.match(reg);    console.log(res);</script>