密码的正则表达式被忽略

Question

我写了这个javascript和html代码来检查用户名和密码的有效性。由于某种原因，密码的正则表达式被igonred。

＆＃13;

＆＃13;

function checkDetails() {
  var uname = document.getElementById("uname").value;
  var pass = document.getElementById("pass").value;
  var reuname = /^[a-zA-Z]\w*$/;
  var repass = /^\w+{4,8}$/;
  if (reuname.test(uname)) alert(uname);
  else {
    alert("username should be alphanumeric and start with alphabet");
    return false;
  }
  if (repass.test(pass)) alert(pass);
  else {
    alert("password should be alphanumeric with 4-8 chars");
    return false;
  }
}

＆＃13;

body {
  background-color: cyan;
}
#content {
  width: 550px;
  margin-left: auto;
  margin-right: auto;
}
h1 {
  text-align: center;
  margin-bottom: 30px;
}
#content table td {
  height: 30px;
}

＆＃13;

<div id="content">
  <h1>Register Form</h1>
  <form method="post" action="" onsubmit="return checkDetails(); return false;">
    <table>
      <tr>
        <td>Enter UserName:</td>
        <td>
          <input type="text" name="uname" size="20" id="uname" />
        </td>
      </tr>
      <tr>
        <td>Enter Password:</td>
        <td>
          <input type="password" name="pass" size="20" id="pass" />
        </td>
      </tr>
      <tr>
        <td>Re-Enter Password:</td>
        <td>
          <input type="password" name="repass" size="20" id="repass" />
        </td>
      </tr>
      <tr>
        <td>Enter E-mail:</td>
        <td>
          <input type="text" name="email" id="email" />
          <td>
      </tr>
      <tr>
        <td>Re-Enter E-mail:</td>
        <td>
          <input type="text" name="reemail" id="reemail" />
          <td>
      </tr>
      <tr>
        <td>Enter Address:</td>
        <td>
          <textarea rows="10" cols="50" name="address" id="address"></textarea>
          <td>
      </tr>
      <tr>
        <td colspan="2" style="text-align: center;">
          <input type="submit" name="submit" value="submit" style="width: 100px; height: 30px;" />
        </td>
      </tr>
    </table>
  </form>
</div>

＆＃13;

＆＃13;

＆＃13;

当我评论这条特定的行时，它会起作用。

/*var repass = /^\w+{4,8}$/;*/

为什么这种奇怪的行为？

Answer 1

检查你的控制台！你应该看到：Uncaught SyntaxError: Invalid regular expression: /^\w+{4,8}$/: Nothing to repeat(…)

我不确定你想要什么，但也许可以试试/^(\w+){4,8}$/

Answer 2

＆＃13;

＆＃13;

function checkDetails() {
  var uname = document.getElementById("uname").value;
  var pass = document.getElementById("pass").value;
  var reuname = /^[a-zA-Z]\w*$/;
  var repass = /^\w{4,8}$/;
  if(reuname.test(uname))alert(uname);
  else {
    alert("username should be alphanumeric and start with alphabet");
    return false;
  }
  if(repass.test(pass))alert(pass);
  else {
    alert("password should be alphanumeric with 4-8 chars");
    return false;
  }
  return true;
}

＆＃13;

body{
  background-color: cyan;
}
#content{
  width: 550px;
  margin-left: auto;
  margin-right: auto;
}
h1 {
  text-align: center;
  margin-bottom: 30px;
}
#content table td{
  height: 30px;
}

＆＃13;

<div id="content">
  <h1>Register Form</h1>
  <form method="post" action="" onsubmit="return checkDetails(); return false;">
    <table>
      <tr>
        <td>Enter UserName:</td>
        <td>
          <input type="text" name="uname" size="20"
          id="uname" />
        </td>
      </tr>
      <tr>
        <td>Enter Password:</td>
        <td>
          <input type="password" name="pass" size="20"
          id="pass" />
        </td>
      </tr>
      <tr>
        <td>Re-Enter Password:</td>
        <td>
          <input type="password" name="repass" size="20"
          id="repass" />
        </td>
      </tr>
      <tr>
        <td>Enter E-mail:</td>
        <td>
          <input type="text" name="email" id="email"
          />
          <td>
      </tr>
      <tr>
        <td>Re-Enter E-mail:</td>
        <td>
          <input type="text" name="reemail" id="reemail"
          />
          <td>
      </tr>
      <tr>
        <td>Enter Address:</td>
        <td>
          <textarea rows="10" cols="50" name="address"
          id="address"></textarea>
          <td>
      </tr>
      <tr>
        <td colspan="2" style="text-align: center;">
          <input type="submit" name="submit" value="submit"
          style="width: 100px; height: 30px;"
          />
        </td>
      </tr>
    </table>
  </form>
</div>

＆＃13;

＆＃13;

＆＃13;

我认为密码的正则表达式无效。你能试试吗？

Answer 3

您必须删除正则表达式的“+”符号。

var repass = /^\w{4,8}$/;