Home > Developer > Ajax

Verify the existence of the user name using Ajax

Source: Internet
Author: User
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

During registration, the user name is often verified. If the entered user name already exists, a prompt is provided immediately instead of waiting for verification after the information is filled in. If there is a lot of input information, not only will the information be lost, it is annoying to perform a callback. You can use ajax to verify the registration to avoid these problems. The following is a simple example to determine whether the user name exists:

From: http://www.cnblogs.com/huazai/archive/2008/11/25/1340911.html

First: original JS Verification

 HmtlCode:

<HTML xmlns = "http://www.w3.org/1999/xhtml">
<Head id = "head1" runat = "server">
<Title> </title>
<Script language = "JavaScript" type = "text/JavaScript" src = "checkusername. js"> </SCRIPT>
<Script language = "JavaScript">
</SCRIPT>
</Head>
<Body>
<Form ID = "form1" runat = "server">
<Table cellpadding = "0" cellspacing = "0" width = "100%">
<Tr>
<TD> Ajax example: </TD>
</Tr>
<Tr>
<TD>
<Table cellpadding = "0" cellspacing = "0" width = "100%">
<Tr>
<TD> Example 1: Check username isexists </TD>
</Tr>
<Tr>
<TD>
<Asp: Label id = "lblusername" runat = "server" text = "username:"> </ASP: Label>
<Input id = "txtusername" type = "text" onblur = "onblur ()"/>
</TD>
</Tr>
</Table>
</TD>
</Tr>
</Table>
</Form>
</Body>
</Html>

 

// Checkusername. js

VaR Ajax = function (option)
{
VaR request;
VaR createrequest = function ()
{
VaR request;
If (window. XMLHttpRequest)
{
Request = new XMLHttpRequest ();
}
Else
{
Try
{
Request = new activexobject ("Microsoft. XMLHTTP ");
}
Catch (E)
{
Request = new activexobject ("msxml2.xmlhttp ");
}
}
Return request;
}

VaR sendrequest = function ()
{
Request = createrequest ();
// Request. Open ("Post", option. url, true );
// Request. setRequestHeader ("Content-Type", "application/X-WWW-form-urlencoded ");
// Request. onreadystatechange = responserequest;
// Request. Send (option. Param );
Request. Open ("get", option. url + "? T = 0 ", true );
Request. onreadystatechange = responserequest;
Request. Send (null );
}

VaR responserequest = function ()
{
If (request. readystate = 4)
{
If (request. Status = 200)
{
Option. Success (request );
}
Else
{
Option. Failure (request );
}
}
}
Sendrequest ();
}

VaR onblur = function ()
{
VaR option = {URL: "test. aspx ", Param:" T = 1 ", success: function (request) {alert (request. responsetext) ;}, faitrue: function (request) {alert (false )}};
New Ajax (option );
}

 

// Test. aspx

Protected void page_load (Object sender, eventargs E)
{
If (request ["T"]! = NULL)
{
This. response. Clear ();
String T = request ["T"]. tostring ();
If (t = "1 ")
{
Response. Write ("the user name already exists. Please enter another user name! ");
}
Else if (t = "0 ")
{
Response. Write ("this user name is not registered. You can use it! ");
}
This. response. End ();
}
}

 

 Method 2: Ajax verification using jquery framework

Hmtl code:

<HTML xmlns = "http://www.w3.org/1999/xhtml">
<Head runat = "server">
<Title> </title>
<SCRIPT src = "jquery-1.2.6.min.js" type = "text/JavaScript"> </SCRIPT>
<SCRIPT>
$ (Document). Ready (function (){
$ ("# Button1"). Click (function (){
$. Ajax ({
Type: "Get ",
URL: "responsepage. aspx? T = 0 ",
Datatype: 'html ',
Success: function (data ){
Alert ("Post" + data );
},
Error: function () {alert ('error! ');}
});
});
});

</SCRIPT>
</Head>
<Body>
<Form ID = "form1" runat = "server">
<Div>
<Input id = "button1" type = "button" value = "display"/>
</Div>
</Form>
</Body>
</Html>

// Responsepage. apsx

Protected void page_load (Object sender, eventargs E)
{
This. response. Clear ();
String T = request ["T"]. tostring ();
If (t = "1 ")
{
Response. Write ("the user name already exists. Please enter another user name! ");
}
Else if (t = "0 ")
{
Response. Write ("this user name is not registered. You can use it! ");
}
This. response. End ();
}

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
wordpress the field meaning of existence in english get distinguished name of user powershell call php function using ajax foundations of ajax verify ssl certificate using openssl calling php function from javascript using ajax
Related Article
JQuery AJAX Timeout Timeout problem detailed _jquery
The difference between traditional web development patterns a...
JQuery ajax File Download _ajax
Ajax various implementation methods compare _ajax
Ajax Getting Started Guide (ii)
SPRINGMVC passing a parameter list object through Ajax or pas...

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

What's Trending
Top 10 Tags
datastax versions naming convention zookeeper client class definition md5 microsoft sql server 2005 data structures exception handling error handling
Top 10 Keywords
microsoft download center down wordpress address url site address url wordpress address url windows installer 4 0 download 302 not found web address url definition site address url wordpress db2 integer mac os installation step by step pdf abbreviation for return

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More