Example sharing JavaScript login verification basic tutorial-JS Tutorial-php.cn

Example sharing JavaScript login verification basic tutorial

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Release： 2017-12-28 11:31:58

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This article mainly introduces the basic tutorial of JavaScript login verification in detail. It has certain reference value. Interested friends can refer to it. I hope it can help everyone.

The example in this article shares the specific code of js login verification for your reference. The specific content is as follows

1. Three usages of<script></script> ：

1. Put it in

2. Put it in

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>欢迎你，请先登陆！</title>
 <script type="text/javascript" src="../static/jsp/lx.js"></script>
 <script type="text/javascript">alert(&#39;这是javascript代码&#39;)</script>
</head>
<body>
<p id="demo">www</p>
<script>
 document.getElementById(&#39;demo&#39;).innerHTML = Date()
</script>
<p id="container" style="width: 400px" align="center">
 <p id="header" style="background-color: aquamarine">
  <h2 align="center">登陆</h2>
 </p>
 <p id="content">
  <form>
   <p align="center">账号:
    <input id="uname" type="tex" name="user" placeholder="请输入用户名">
   </p>
   <p align="center">密码:
    <input id="upass" type="password" name="psw">
   </p>
   <p id="error_box"><br></p>
   <br>
   <button onclick="fnLogin()">登陆</button>
   &nbsp&nbsp&nbsp
   <input type="button" name="regist" value="注册">
  </form>
 </p>
 <p style="background-color: aquamarine">
  <i>版权信息@</i>
 </p>
</p>
</body>
</html>

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3. Place it in an external JS file

document.getElementById('demo').innerHTML = Date()

Run screenshot:

Three ways to output data:

1. Use the document.write() method to write the content into the HTML document.

2. Use window.alert() to pop up a warning box.

3. Use innerHTML to write to HTML elements.

1). Use the "id" attribute to identify HTML elements.

2). Use document.getElementById(id) method to access HTML elements.

3). Use innerHTML to obtain or insert element content.

The code is as follows

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>欢迎你，请先登陆！</title>
 <script type="text/javascript" src="../static/jsp/lx.js"></script>
 <script type="text/javascript">alert(&#39;这是javascript代码&#39;)</script>
</head>
<body>
<p id="demo">www</p>
<script>
 document.getElementById(&#39;demo&#39;).innerHTML = Date()
</script>
<button type="button" onclick=window.alert("number")>press</button>
</body>
</html>

Copy after login

Run screenshot:

3. Login page preparation:

1. Add an error prompt box.

2. Write the HTML+CSS file.

3. Set the id of each input element

4. Define JavaScript function.

1. Verify 6-20 digits of username

2. Verify 6-20 digits of password

5. Call this function on click.

The html code is as follows:

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>欢迎你，请先登陆！</title>
 <script type="text/javascript" src="../static/jsp/lx.js"></script>
 <link rel="stylesheet" type="text/css" href="../static/css/lx.css" rel="external nofollow" >
</head>
<body>
<p class="p" id="container">
 <p id="header" >
  <h2 class="h">登陆</h2>
 </p>
 <p id="content">
   <p class="p">账号:
    <input id="uname" type="text" placeholder="请输入用户名">
   </p>
   <p class="p">密码:
    <input id="upass" type="password" >
   </p>
   <p id="error_box"><br>
   </p>
   <button onclick="fnLogin()">登陆</button>
   &nbsp&nbsp&nbsp
   <input type="button" name="regist" value="注册">
 </p>
 <p>
  <i>版权信息@</i>
 </p>
</p>

</body>
</html>

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The js file code is as follows:

function fnLogin() {
 var oUname = document.getElementById("uname")
 var oUpass = document.getElementById("upass")
 var oError = document.getElementById("error_box")
 if (oUname.value.length > 20 || oUname.value.length < 6) {
  oError.innerHTML = "请输入6-20位字符"
 }

 if (oUpass.value.length > 20 || oUpass.value.length < 6) {
  oError.innerHTML = "请输入6-20位字符"
 }
}

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The CSS code is as follows:

.p {
 border: 5px solid #cccccc;
 width: 400px;
 text-align: center;
}
.p{
 font-family:华文楷体 ;
}
.h{
 font-family: 华文楷体;
}

Copy after login

Running screenshot:

## Related recommendations:

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Implementation of JavaScript login verification code

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