JavaScript Basics, login verification (2017.10.24)

Last Update:2017-10-25 Source: Internet

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1, <script></script> three ways to use:

Put in the <body>

Put in the

Placed in an external JS file

<! DOCTYPE html>"en">"UTF-8"> <title>javascpit2017.10.24</title> <script>function Displaydate () {document.getElementById ("Hello"). innerhtml=Date (); }    </script>"Demo">dailier</p><script>document.write ("<p> Guangzhou Business School </p>"); document.getElementById ("Demo"). innerhtml=Date ();</script><button type="Button"Onclick=window.alert (" Number") > Login </button></body>function MyFunction () {Document.getelementbyld ("demo"). Innerhtml=" my first JavaScript function " ;}
2, three ways to output data:
Use the document.write () method to write content to an HTML document.
Use the Window.alert () pop-up warning box.
Writes to an HTML element using InnerHTML.

 
 
  
   
   Use the ID property to identify the HTML element. 
   Use the document.getElementById (ID) method to access HTML elements. 
   Use innerHTML to get or insert element content. 
  
 
 
The code is as follows:
<! DOCTYPE html>"en">"UTF-8"> <title> my page </title>Document.wirte (Date ())&LT;/SCRIPT&GT;&LT;H1 align="Center">2017 New Edition "Container"style="width:400px"> <div id="Header"style="background-color:indianred"&GT;&LT;H2 align="Center"> Login "content"> <form>Username:<input type="text"Name="username"Placeholder="Please enter user name"><br>Password:<input type="Password"Name="pwd"Placeholder="Please enter your password"><br> <input type="Radio"Name="role"Value="Stu">Student<input type="Radio"Name="role"Value="Tea">teacher<br> <input type="checkbox"Name="Vehicle"Value="Remember me"> Remember me <br> <input type="Button"Value="Login"><br> <aclass="Link-forget Cl-link-blue"href="get_password.html"> Forgot password </a> <aclass="Link-forget Cl-link-blue"href="Index.php?type=login"> New User Registration </a> </form> </div> <div id="Footer"style="background-color:indianred"><p align="Center"><i> Copyright Pear </i></p></div> </div> <div> </div><script>Window.alert ("Are you sure you want to go to this site? ")</script><script>Document.wirte (Date ());</script><p id="Demo">dailier</p><script>document.getElementById ("Demo"). innerhtml=Date ();</script></body>
The results are as follows:
3, the login page to prepare:
Add an Error prompt box.
Write a good html+css file.
Set the ID of each INPUT element
4. Define JavaScript functions.
Verify user name 6-20-bit
Verify password 6-20-bit
The code is as follows:
<! DOCTYPE html>"en">"UTF-8"> <title> Search Encyclopedia </title> <link rel="stylesheet"Type="Text/css"href=".. /static/css/20.css"> <script>function Fnlogin () {var ouname=document.getelementbyid ("uname") var oerror=document.getelementbyid ("Error_box") var opassward= document.getElementById ("UPass")            if(Ouname.value.length<6 | | ouname.value.length>20) {oerror.innerhtml="User name 6-20-bit"            }            if(Oupass.value.length<6 | | oupass.value.length>20) {oerror.innerhtml="password 6-20 bit"             }             if((ouname.value.length<6 | | ouname.value.length>20) && (oupass.value.length<6 | | oUpass.value.length >20) ) {oerror.innerhtml="user name and password must be 6-20 bit! "}        }    </script>class="Box"> class="Input_box"> <input id="uname"Type="text"Placeholder="Please enter user name"style="width:300px"> </div> <br> <divclass="Input_box"> <input id="UPass"Type="Password"Placeholder="Please enter your password"style="width:300px"> </div> <br> <div id="Error_box"><br></div> <divclass="Input_box"> "Fnlogin ()">login</button>class="Link-forget Cl-link-blue"href="get_password.html"> Forgot password </a> <aclass="Link-forget Cl-link-blue"href="Index.php?type=login"> New User Registration </a> <br> <div><p align="Center"><i> Copyright @daili18</i></p></div></div>document.write ("College beauty: Little East Lake")</script>Window.alert ("Are you sure you want to enter? ")</script></body>
Css:
body{    padding-right:500px;    Margin-top:100px;    Padding-left:500px;    Font-size:16px;    background:palevioletred;    Padding-bottom:120px;    Color:firebrick;    Padding-top:40px;    Font-family:verdana,arial,helvetica,sans-serif;    } h3 {       padding-left:120px;} h4{    padding-left:80px;    Color:firebrick;} h5{    padding-left:120px;}
The results are as follows:
5, the onclick call this function.
The code is as follows:
<! DOCTYPE html>"en">"UTF-8"> <script>function Duang () {alert ('There's nothing you're looking for here.')}</script>"Input_box"Type="Button"Value="Is you really? "onclick="Duang ()"></body>
The results are as follows:
JavaScript Basics, login verification (2017.10.24)

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