将jQuery validate插件与"remote"结合使用选项 [英] Using the jQuery validate plugin with the "remote" option

问题描述

我正在使用jQuery validate插件及其远程选项来检查输入字段中是否存在用户名.我使用以下代码:

I am using the jQuery validate plugin and its remote option for checking the existence of a username from an input field. I use this code:

 remote : {
      url :'ajax_php/admin/checking.php',
      type   :'post',
      data   : {
      type:'username'   
}}

即使我将类型请求设置为post，我也注意到请求URL附加了回调参数:

I've noticed that the request URL has a callback parameter appended, even though I set the type request to post:

http://localhost/lopoli2/ajax_php/admin/checking.php?callback=jQuery15104128487491980195_1311232389069

我的PHP脚本可以正常工作，并为有效的用户名返回true，并为无效的用户名返回一个字符串.但是没有错误消息出现！简而言之，我的PHP文件如下所示:

My PHP script works fine and returns true for valid username and a string for invalid usernames. But no error message appears! My PHP file in short looks like this:

$check = mysql_query("select `username` from `user_tbl` where `username`='".$_POST['username']."' ",$conn) 
or die('Error In DB !');

if (mysql_num_rows($check)>0){
    echo("username is already exists");
}else{
    echo("true");
}

这就是我想知道的:

• 回调参数有什么用?
• 如何解决显示错误消息"问题?

推荐答案

返回的值被认为是布尔值(true/false)或字符串(将被处理为false并显示返回的文本).

The returned value is considered to be a boolean (true/false) or a string (will be handled as false and display the returned text).

同样重要的是，使用header('content-type:text/plain');

Also, it is important to set the output to text/javascript or text/plain using header('content-type:text/plain');

因此在php中，返回值时，应注意返回值的类型，如下所示:

So in php, when returning the value, you should pay attention to the type of the returned value as follows:

echo'true'; //=> true，一个布尔值. 说验证的结果是真实的，一切都很好.

echo 'true'; //=> true, a boolean. Says the result of the validation is true and everything is okay.

回显'false'; //=> false，一个布尔值. 说验证结果是错误的，并显示在验证器对象中配置的消息

echo 'false'; //=> false, a boolean. Says the result of the validation is wrong and display a message configured in the validator object

回显'"false"'; //=>"false"，一个字符串. 说验证结果是错误的，并且显示返回的字符串将显示为错误.

echo '"false"'; //=> "false", a string. Says the result of the validation is wrong and display the returned string will be displayed as an error.

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