对jquery .ajax .done()函数感到困惑 [英] Confused on jquery .ajax .done() function

问题描述

我对如何使用ajax .done()函数有些困惑.我正在验证表单以检查用户是否存在于数据库中，尽管ajax是最好的方法(仍在学习中).我有一个php文件，如果用户存在，则返回true；如果用户不存在，则返回false.如何将布尔值传递给完成函数的参数?

I'm a bit confused on how to use the ajax .done() function. I'm working on validating a form to check if a user exists in database and though ajax would be the best approach (still learning it). I have a php file that return true if user exists and false if user doesn't exist. How would I pass the boolean into the parameter for the done function?

$(".check").blur(function(){
  var username = $(".check").val();
  $.ajax({
    url: "validateUser.php",
    type: "post",
    data: "username= " + username
  }).done(function(result){
    if (result == true){
      // User exists
    }else{
      // User doesn't exist
    }
  });
});

我希望这是有道理的.我尽力解释了这一点.

I hope that made sense. I did my best to explain it.

推荐答案

我认为应该是result =='true'，因为结果是数据字符串

I think it should be result == 'true' as the result is a data string

我刚刚检查了，我是对的，引号使它有效

I just checked, I am correct, the quotes make it work

PHP:

<?php

if($_POST['username']=='sambob'){echo 'true';}else{echo 'false';}

?>

JavaScript

Javascript

username='sambob';

$(".check").blur(function(){
  $.post("validateUser.php", { username: username })
  .done(function(data) {
     if (data == 'true'){
        alert("User exists");
     }else{
        alert("User doesn't exist"); 
     }
  });
});

json PHP

<?php

if($_POST['username']=='sambob'){echo'{"exists":true}';}
                            else{echo'{"exists":false}';}
?>

json Javascript

json Javascript

$(".check").blur(function(){
   $.post("validateUser.php", { username : username },
   function(user){
      if (user.exists == true){
         alert("User exists");
      }else{
         alert("User doesn't exist");
      }
   }, "json");
});

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