现场的用户名查找与AJAX / jQuery的 [英] Live username lookup with AJAX/Jquery

问题描述

我想有一个JavaScript函数像这样的：

I want to have a javascript function such as this:

function isUsernameAvailable(username)
{
   //Code to do an AJAX request and return true/false if
  // the username given is available or not
}

怎么可以这样使用jQuery或xajax的完成？

How can this be accomplished using Jquery or Xajax?

推荐答案

在使用AJAX的是，它是异步的重大胜利。你问了一个同步函数调用。这是可以做到的，但它可能会锁定在浏览器而这是等待服务器

The big win when using AJAX is that it is asynchronous. You're asking for a synchronous function call. This can be done, but it might lock up the browser while it is waiting for the server.

使用jQuery的：

function isUsernameAvailable(username) {
    var available;
    $.ajax({
        url: "checkusername.php",
        data: {name: username},
        async: false, // this makes the ajax-call blocking
        dataType: 'json',
        success: function (response) {
            available = response.available;
        }
     });
     return available;
}

您PHP的code应再检查数据库，并返回

Your php-code should then check the database, and return

{available: true}

如果名称是确定的。

这是说，你应该这样做异步的。像这样：

That said, you should probably do this asynchronously. Like so:

function checkUsernameAvailability(username) {
    $.getJSON("checkusername.php", {name: username}, function (response) {
        if (!response.available) {
            alert("Sorry, but that username isn't available.");
        }
    });
}

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