When registering a user, we will prompt whether the user's information is available in real time. This is the ajax application. I have seen this implementation a long time ago and read it again today, record 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
First introduce the $. get in ajax, because the $. post usage and $. get are similar and will not be introduced (from http://www.w3school.com.cn ):
This is a simple GET request function to replace complex $. ajax. You can call the callback function when the request is successful. To execute a function when an error occurs, use $. ajax.
$(selector).get(url,data,success(response,status,xhr),dataType)
| Parameters | Description |
|---|---|
| Url | Required. Specifies the URL of the request. |
| Data | Optional. Specifies the data sent to the server together with the request. |
| Success (response, status, xhr) | Optional. Specifies the function that runs when the request is successful. Additional parameters:
|
| DataType | Optional. Specifies the expected server response data type. By default, jQuery performs intelligent judgment. Possible types:
|
Request the test. php webpage and ignore the returned value:
$.get("test.php");More Example 1
Send two parameters to the test. php webpage and ignore the returned value:
$.get("test.php", { name: "John", time: "2pm" } );Example 2
Display the test. php return value (HTML or XML, depending on the return value ):
$.get("test.php", function(data){ alert("Data Loaded: " + data);});Example 3
Display the return value of test. cgi (HTML or XML, depending on the returned value), add a set of request parameters:
$.get("test.cgi", { name: "John", time: "2pm" }, function(data){ alert("Data Loaded: " + data); });
The following is my code:
<Head> <meta http-equiv = "Content-Type" content = "text/html; charset = UTF-8 "/> <title> User Registration </title> <script type =" text/javascript "src =" jquery/jquery-1.5.2.js "> </script> <script type = "text/javascript"> $ (document ). ready (function () {$ ("# username "). focus (); $ ("# username "). keyup (function () {name = $ ("# username "). val (); // The val () method returns or sets the value of the selected element. If (len (name) <4) // call the following custom len Function ~ \ (Too many rows )/~ $ ("# Username1" ).html ("<font color = red> the registration name must be greater than or equal to 2 Characters </font> "); else $ ("# username1" ).html ("<font color = red> compliant </font>"); // html () method to return or set the content of the selected element (inner HTML ).}); $ ("# Username "). blur (function () {name = $ ("# username "). val (); $. get ("t1.php", {username: name}, function (data) {// determine whether this user name exists in the Database $. get, $. post t1.php in the following if (data = 1) {$ ("# username1" ).html ("<font color = green> compliant </font> ");} else {$ ("# username1" ).html ("<font color = green> occupied </font> ");}});});}); function len (s) {// if the character is a Chinese character, it occupies two var l = 0; var a = s. split (""); for (var I = 0; I <. length; I ++) {if (a [I]. charCodeAt (0) <299) {l ++;} else {l + = 2 ;}} return l ;} </script>
T1.php:
<? 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);?>
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