php学习笔记
函数的应用
函数中的变量定义后也只能在它的作用范围内才可以使用
$var = 100; //此处$var是全局变量
function test($var){
echo "在函数var的内部的值为:".$var; //在函数内部调用全局变量$var
}
test();
?>
//如何在函数内部使用函数外部的变量
1.在函数内部使用关键字global修饰变量
$var = 100; //此处$var是全局变量
function test($var){
global $val; //在test()范围内，使用函数在外面的变量
echo "在函数var的内部的值为:".$var; //在函数内部调用全局变量$var
}
test();
?>
2.//使用预定义变量 G L O B A L S 预 定 义 变 量 GLOBALS 预定义变量 GLOBALS预定义变量GLOBALS用于引用全局作用域中可用的全部变量
$var = 100; //此处$var是全局变量
function test($var){
echo "在函数var的内部的值为:".$GLOBALS['var'];
}
test();
?>
会话练习
登录设置
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<form action="login.php" method="post">
<label>用户名：</label>
<input type="text" name="username" />
<label>密码：</label>
<input type="text" name="password" />
<input type="submit" name="submit" value="登录">
</form>
</body>
</html>
$arr = array("username"=>"xiangming","password"=>"123456");
if (isset($_POST['submit'])) {
$username = $_POST['username'];
$password = $_POST['password'];
if ($username == $arr['username']) {
if ($password == $arr['password']) {
session_start();
echo "";
echo "";
# code...
}else {
echo "";
echo "";
}
# code...
}
else{
echo "";
echo "";
}
# code...
}
?>
session_start();
if (!isset($_SESSION['username'])=='') {
echo "";
echo "";
# code...
}
echo "登录成功后的页面";
?>
数组分页
$arr = array(
array("001","aaa",1,"php"),
array("002","aaa",1,"php"),
array("003","aaa",1,"php"),
array("004","aaa",1,"php"),
array("005","aaa",1,"php"),
array("006","aaa",1,"php"),
array("007","aaa",1,"php"),
array("008","aaa",1,"php"),
array("009","aaa",1,"php"),
array("010","aaa",1,"php"),
array("011","aaa",1,"php"),
array("012","aaa",1,"php"),
array("013","aaa",1,"php"),
);
$page = $_GET['page'];
$perpage = 3;
$page_num = ceil(count($arr)/$perpage);
$page = max(1,$page);
$page = min($page_num,$page);
$start_index = ($page-1)*$perpage;
$end_index = $page*$perpage-1;
// echo $start_index;
// echo "
";
// echo $end_index;
?>
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<table border="1">
<tr>
<th>学号</th>
<th>姓名</th>
<th>班级</th>
<th>科目</th>
</tr>
for($i = $start_index; $i<= $end_index; $i++){
# code...
?>
<tr>
<td> echo $arr[$i][0];?></td>
<td> echo $arr[$i][1];?></td>
<td> echo $arr[$i][2];?></td>
<td> echo $arr[$i][3];?></td>
</tr>
}?>
</table>
<a href="?page=1">【首页】</a>
<a href="?page=$page-1);?>">【上一页】</a>
<a href="?page=$page+1);?>">【下一页】</a>
<a href="?page=$page_num;?>">【尾页】</a>
</body>
</html>