Use jQuery. Validate to asynchronously verify whether the user name exists (recommended). jquery. validate is asynchronous.

Use jQuery. Validate to asynchronously verify whether the user name exists (recommended). jquery. validate is asynchronous.

HTML header reference:

<script type="text/JavaScript" src="../js/jQuery-1.3.2.min.js"></script><script type="text/javascript" src="../js/jquery.validate.min.js"></script><script type="text/javascript" src="../js/messages_cn.js"></script>

HTML content (Part ):

<Form name = "form1" id = "form1" method = "post" action = ""> <dl> <dt> User name: </dt> <dd> <input name = "txtUserName" id = "txtUserName" type = "text" class = "input1"/> </dd> </dl> </form>

JS Code:

$ (Function () {// Form Verification JS $ ("# form1 "). validate ({// tag errorElement: "span", rules: {txtUserName: {required: true, minlength: 3, maxlength: 16, remote: {type: "post", url: "/tools/ValidateUserName. ashx ", data: {username: function () {return $ (" # txtUserName "). val () ;}, dataType: "html", dataFilter: function (data, type) {if (data = "true") return true; else return false ;}}}, success: function (label) {// The style label when the label is correct. text (""). addClass ("success") ;}, messages: {txtUserName: {required: "Enter the username, which must contain 3-16 characters (letters, numbers, and underscores). It cannot be changed after registration ", minlength: "User Name Length cannot be less than 3 characters", maxlength: "User Name Length cannot be greater than 16 characters", remote: "User Name unavailable "}}});});

Notes:

data: {  username: function() {  return $("#txtUserName").val();}

There is a return value. If you write it directly“data: {username: $("#txtUserName").val();}”，In this case, the value cannot be obtained.

The above section describes how to use jQuery. validate asynchronously verifies whether the user name exists. I hope it will help you. If you have any questions, please leave a message and I will reply to you in a timely manner. Thank you very much for your support for the help House website!