无法在非jQuery函数中使用jQuery post的问题 [英] Trouble using jQuery post inside non jQuery function

问题描述

我在HTML页面中有以下脚本:

I have the following script inside a HTML page:

<script>

function Test(){

alert("i got here");

 var username = document.registration_form.username.value;

 alert(username);

 $.post("checkname.php", { name:  username }, function(data) {

   alert("and here");

   alert(data);

   if (data = "0"){
       alert('That username is already in use, please choose another');
    return false;
   };
   if (data = "1") {
    return true;   
   };

});
};

</script>

如果数据库中已经有用户名，我正在尝试进行功能测试以返回true或false.

I'm trying to get the function test to return true or false if a username is already in my database.

checkname.php包含以下内容:

checkname.php contains the following:

<?

$host="localhost"; // Host name
$username=""; // Mysql username
$password=""; // Mysql password
$db_name=""; // Database name

mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

$myusername=$_POST['name'];


$sql="SELECT * FROM members WHERE username='".$myusername."'";


$result=mysql_query($sql);


$count=mysql_num_rows($result);


if($count >= 1){
echo "0";
}
else {
echo "1";
}

?>

我已经尝试过对名称进行硬编码并运行PHP，并且效果很好.

I've tried hardcoding a name and running the PHP and it works fine.

尽管出于某种原因，当我运行Test()时，前2个警报运行正常，向我显示了已设置的用户名，但随后的警报均未显示.

For some reason though when I run Test() the first 2 alerts come through fine, showing me the username enetered, but none of the subsequent alerts appear.

Oooo和jQuery已添加到标题中，如下所示:

Oooo and jQuery has been added in the header like so:

<script src="create/js/jquery-1.4.4.min.js" type="text/javascript" ></script>
<script src="create/js/jquery-ui-1.8.7.custom.min.js" type="text/javascript"></script>

任何帮助，不胜感激:)

Any help much appreciated :)

推荐答案

首先，从回调到$ .post的return语句将 not 从Test()函数返回.您应该使用处理服务器中数据的回调函数来调用Test，如下所示:

First of all, your return statements from the callback to $.post will not return from your Test() function. You should call Test with a callback function that deals with the data from the server, something like this:

function Test(username, callback) {
  $.post("checkname.php", {name: username}, callback);
}

Test(document.registration_form.username.value, function(data) {
  if(data == "0") {
    // Do something
  } else {
    // Do something else
  }
});

布拉德在比较方面也是正确的-您当前为数据分配了"0".我认为，即使有其他错误，您也应该收到警报.也许您需要checkname.php脚本的绝对路径?例如. "/checkname.php"(注意斜线)?

Brad is also correct about the comparison - you're currently assigning "0" to data. You should get the alerts though, I think, even with the other errors. Maybe you need the absolute path to the checkname.php script? E.g. "/checkname.php" (note the slash)?

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