php的知识

javascript中写php:

<script language="javascript">

function check(){

<?php

if($_SESSION["id"]){

?>

alert('您已登录！');

<?php }  else {?>

alert('请登陆');

<?php } ?>

}

</script>

PHP上传文件:

<form method="post" name="form" action="" enctype="multipart/form-data">
<input name="userfile[]" type="file">
<input type="submit" value="提交">
</form>

<?php

$uploaddir = '/upload/';
$uploadfile = $uploaddir . basename($_FILES['userfile']['name']);

if (move_uploaded_file($_FILES['userfile']['tmp_name'], $uploadfile)) {
echo "File is valid, and was successfully uploaded./n";
} else {
echo "Possible file upload attack!/n";
}
?>