download：人人都能学会数据分析
<
!
DOCTYPE
html
>
<
html
>
<
head
>
<
meta
charset
=
"
utf-8
"
>
<
title
>
菜鸟教程(runoob.com)
</
title
>
<
script
>
function
showSite
(
str
)
{
if
(
str
==
"
"
)
{
document
.
getElementById
(
"
txtHint
"
)
.
innerHTML
=
"
"
;
return
;
}
if
(
window
.
XMLHttpRequest
)
{
//
IE7+, Firefox, Chrome, Opera, Safari 浏览器执行代码
xmlhttp
=
new
XMLHttpRequest
(
)
;
}
else
{
//
IE6, IE5 浏览器执行代码
xmlhttp
=
new
ActiveXObject
(
"
Microsoft.XMLHTTP
"
)
;
}
xmlhttp
.
onreadystatechange
=
function
(
)
{
if
(
xmlhttp
.
readyState
==
4
&&
xmlhttp
.
status
==
200
)
{
document
.
getElementById
(
"
txtHint
"
)
.
innerHTML
=
xmlhttp
.
responseText
;
}
}
xmlhttp
.
open
(
"
GET
"
,
"
getsite_mysql.php?q=
"
+
str
,
true
)
;
xmlhttp
.
send
(
)
;
}
</
script
>
</
head
>
<
body
>
<
form
>
<
select
name
=
"
users
"
onchange
=
"
showSite(this.value)
"
>
<
option
value
=
"
"
>
选择一个网站:
</
option
>
<
option
value
=
"
1
"
>
Google
</
option
>
<
option
value
=
"
2
"
>
淘宝
</
option
>
<
option
value
=
"
3
"
>
菜鸟教程
</
option
>
<
option
value
=
"
4
"
>
微博
</
option
>
<
option
value
=
"
5
"
>
Facebook
</
option
>
</
select
>
</
form
>
<
br
>
<
div
id
=
"
txtHint
"
>
<
b
>
网站信息显示在这里……
</
b
>
</
div
>
</
body
>
</
html
>
showSite() 函数会执行以下步骤：
- 检查是否有网站被选择
- 创建 XMLHttpRequest 对象
- 创建在服务器响应就绪时执行的函数
- 向服务器上的文件发送请求
- 请注意添加到 URL 末端的参数（q）（包含下拉列表的内容）
PHP 文件
上面这段通过 JavaScript 调用的服务器页面是名为 "getsite_mysql.php" 的 PHP 文件。
"getsite_mysql.php" 中的源代码会运行一次针对 MySQL 数据库的查询，然后在 HTML 表格中返回结果：
getsite_mysql.php 文件代码:
<?php
$q
=
isset
(
$_GET
[
"
q
"
]
)
?
intval
(
$_GET
[
"
q
"
]
)
:
'
'
;
if
(
empty
(
$q
)
)
{
echo
'
请选择一个网站
'
;
exit
;
}
$con
=
mysqli_connect
(
'
localhost
'
,
'
root
'
,
'
123456
'
)
;
if
(
!
$con
)
{
die
(
'
Could not connect:
'
.
mysqli_error
(
$con
)
)
;
}
//
选择数据库
mysqli_select_db
(
$con
,
"
test
"
)
;
//
设置编码，防止中文乱码
mysqli_set_charset
(
$con
,
"
utf8
"
)
;
$sql
=
"
SELECT * FROM Websites WHERE id = '
"
.
$q
.
"
'
"
;
$result
=
mysqli_query
(
$con
,
$sql
)
;
echo
"
<table border='1'> <tr> <th>ID</th> <th>网站名</th> <th>网站 URL</th> <th>Alexa 排名</th> <th>国家</th> </tr>
"
;
while
(
$row
=
mysqli_fetch_array
(
$result
)
)
{
echo
"
<tr>
"
;
echo
"
<td>
"
.
$row
[
'
id
'
]
.
"
</td>
"
;
echo
"
<td>
"
.
$row
[
'
name
'
]
.
"
</td>
"
;
echo
"
<td>
"
.
$row
[
'
url
'
]
.
"
</td>
"
;
echo
"
<td>
"
.
$row
[
'
alexa
'
]
.
"
</td>
"
;
echo
"
<td>
"
.
$row
[
'
country
'
]
.
"
</td>
"
;
echo
"
</tr>
"
;
}
echo
"
</table>
"
;
mysqli_close
(
$con
)
;
?>
来源：oschina
链接：https://my.oschina.net/u/4729490/blog/4953089