使用jquery进行验证(validation using jquery)

 概述代码中的错误，并提供经过测试的工作解决方案： 
 
 
 
 你正在调用prepare()函数两次。 
 
 
 为SELECT使用错误的变量。 
 ...使用$sql ，它应该是$stmt 
 
 
 不可能调用你的getManger()函数。 
 
 
 使用连字符而不是等号$age - $row['age']; => $age = $row['age']; 
 
 
 改写： 
 
<?php 
$db_host = "localhost";
$db_username = "root";
$db_pass = "";
$db_name = "testdb";

$dbh = new PDO('mysql:host='.$db_host.';dbname='.$db_name,$db_username,$db_pass);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);

  function getManger($dbh) {

    $stmt= $dbh->prepare("SELECT * FROM test_tbl");
    $stmt->execute();    

    while( $row = $stmt->fetch(PDO::FETCH_ASSOC) ) { 

        $id   = $row['id'];
        $name = $row['name'];
        $age  = $row['age'];

        echo "<li>$id</li>";
        echo "<li>$name</li>";
        echo "<li>$age</li>";
    }
}

// call the function
getManger($dbh); 
 
 
 脚注 ： 
 
 通常最好将你的数据库连接变量传递给你的函数，而不是把它变成全局变量。 
 
 以下是关于全球的Stack上的一些文章： 
 
 
 
 https://stackoverflow.com/a/5166527/ 
 
 
 https://stackoverflow.com/a/5166276/ 
 
 
 这是你的选择。 

To outline the errors in your code, and offer a tested and working solution:
 
 
 
You're calling the prepare() function twice.
 
 
Using the wrong variable for your SELECT.
 ...using $sql where it should be $stmt
 
 
Not possibly calling your getManger() function.
 
 
Using a hyphen instead of an equal sign $age - $row['age']; => $age = $row['age'];
 
 
Rewrite:
 
<?php 
$db_host = "localhost";
$db_username = "root";
$db_pass = "";
$db_name = "testdb";

$dbh = new PDO('mysql:host='.$db_host.';dbname='.$db_name,$db_username,$db_pass);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);

  function getManger($dbh) {

    $stmt= $dbh->prepare("SELECT * FROM test_tbl");
    $stmt->execute();    

    while( $row = $stmt->fetch(PDO::FETCH_ASSOC) ) { 

        $id   = $row['id'];
        $name = $row['name'];
        $age  = $row['age'];

        echo "<li>$id</li>";
        echo "<li>$name</li>";
        echo "<li>$age</li>";
    }
}

// call the function
getManger($dbh); 
 
 
Footnotes:
 
It's usually best to pass your DB connection variable inside your function, rather than making it global.
 
Here are a few articles on Stack about global:
 
 
 
https://stackoverflow.com/a/5166527/
 
 
https://stackoverflow.com/a/5166276/
 
 
The choice is yours.