Registration Real-time verification (Ajax,jquery)

When we register a user, will prompt that the user's information is available, this is the AJAX application, has seen this realization long ago, today looked again, to record down O (∩_∩) o ha.

I also have this introduction on my original blog ... http://hi.baidu.com/%BD%A3%BE%B2%B7%E3/blog/item/a8ddd2eb8a379d00fdfa3c06.html

To introduce the $.get in Ajax, because $.post usage and $.get are similar to no longer introduced (from the http://www.w3school.com.cn):

This is a simple GET request function to replace the complex $.ajax. Callback functions can be invoked when the request succeeds. If you need to perform a function when an error occurs, use $.ajax.

$ (selector). Get (Url,data,success (RESPONSE,STATUS,XHR), DataType)

Parameters	Description
Url	Necessary. Specify which URL to send the request to.
Data	Optional. Specify the data to be sent to the server along with the request.
Success (RESPONSE,STATUS,XHR)	Optional. A function that is required to run when a request succeeds. Extra parameters: Response-Contains the result data from the request status-contains the requested State XHR-contains the XMLHttpRequest object
DataType	Optional. Specify the data type of the expected server response. By default, JQuery will intelligently judge. Possible types: "xml" "HTML" "text" "Script" "JSON" "JSONP"

Request test.php Web page, ignore return value:

$.get ("test.php");

more examples Example 1

Request test.php Web page, transfer 2 parameters, ignore return value:

$.get ("test.php", {name: "John", Time: "2pm"});

Example 2

Displays the test.php return value (HTML or XML, depending on the return value):

$.get ("test.php", function (data) {
  alert ("Data Loaded:" + data);
});

Example 3

Displays the test.cgi return value (HTML or XML, depending on the return value), and adds a set of request parameters:

$.get ("test.cgi", {name: "John", Time: "2pm"},
  function (data) {
    alert ("Data Loaded:" + data);
  });

Post My Code below:

<?php
$link =mysql_connect ("localhost", "root", "");
mysql_select_db ("test");
mysql_query ("Set names UTF8");/
$sql = "SELECT * from user where user= '". $_get[' username ']. "'; /
    $result =mysql_query ($sql) or Die (Mysql_error ());
$num =mysql_affected_rows ();
if ($num ==0)
$msg =1;
else 
    $msg =0;
echo $msg;/return value
mysql_close ($link);
? >