<?php
if (isset($_POST['name'])){
$str = trim($_POST['name']);
$str = strip_tags($str);
$str = htmlspecialchars($str);
$str = addslashes($str);
echo $str;
}
?>
<form method="post" action="">
<input name="name" type="text">
<input type="submit" value="提交" >
</form>