如果出现数据库配置不正确的错误，请看php与mysql的配置教程：
　　win7系统下如何配置php-Apache-mysql环境 http://www.cnblogs.com/myall/p/4744837.html
<form action="" method="post">
<select name="host">
<option value="localhost" selected>localhost</option>
<option value="127.0.0.1">127.0.0.1</option>
</select>
<br><br>
user:<input type="text" name="user" value=""><br><br>
pwd :<input type="password" name="pwd" value=""><br><br>
<input type="submit" value="connent">
<input type="reset" value="reset">
</form>
<?php
error_reporting(~E_ALL);
$host = $_POST['host'];
$user = $_POST['user'];
$pwd = $_POST['pwd'];
if(isset($_POST['host']) && isset($_POST['user']) && isset($_POST['pwd'])){
if(strlen($host)<1 or strlen($user)<1 or strlen($pwd)<1){
echo "请完善相关数据库链接信息。";
exit(0);
}
$conn = mysql_connect($host， $user， $pwd) or die("Error-数据库连接失败！");
if($conn){
echo "OK—数据库连接成功！";
}
}
?>