沒錯...用php來寫 web當然也要hello world....
開啟hello.php.....
路徑放在你的web server 的目錄下.....如果以 apache2 server來說...就是
/var/www/html/
填入以下的內容
<html>
<head>
<title>PHP Test</title>
</head>
<body>
<?php echo '<p>Hello World</p>'; ?>
</body>
</html>
用web browser
http://localhost/hello.php or http://127.0.0.1/hello.php
如果你有看到下面的Hello World...恭喜你....你成功了...
其實你的web browser接收到的是
<html> <head> <title>PHP Test</title> </head> <body> <p>Hello World</p> </body> </html>
在<p>Hello World</p>
後面加入 <?php phpinfo(); ?>
就可以看到php 的 information.....
秀出變數的方法....
<?phpecho $_SERVER['HTTP_USER_AGENT'];?>
$_SERVER is just one variable that PHP automatically makes available to you
Example #2 Example using control structures and functions
<?phpif (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== FALSE) {
echo 'You are using Internet Explorer.<br />';}
else{
echo 'You are not using Internet Explorer.<br />';
}?>
strpos() is a function built into PHP which searches a string for another string
Example #3 Mixing both HTML and PHP modes
<?phpif (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== FALSE) {?><h3>strpos() must have returned non-false</h3>
<p>You are using Internet Explorer</p>
<?php} else {?><h3>strpos() must have returned false</h3>
<p>You are not using Internet Explorer</p>
<?php}?>
Dealing with Forms
<form action="action.php" method="post"> <p>Your name: <input type="text" name="name" /></p> <p>Your age: <input type="text" name="age" /></p> <p><input type="submit" /></p> </form>
action.php 的內容如下:
Hi <?php echo htmlspecialchars($_POST['name']); ?>.
You are <?php echo (int)$_POST['age']; ?> years old.
按下"提交"
htmlspecchars -> 轉型成字串的type .... $_POST['name'] -> input type="text" name="name" 的變數內容
echo (int)$_POST['age'];
(int) -> 轉型成int 的type... $_POST['age'] -> input type="text" name="age"
Using old code with new versions of PHP
Two of the most important recent changes that affect old code are:
- The old $HTTP_*_VARS arrays are not available as of PHP 5.4.0. The following superglobal arrays were introduced in PHP » 4.1.0. They are: $_GET, $_POST, $_COOKIE, $_SERVER, $_FILES, $_ENV, $_REQUEST, and $_SESSION.
- External variables are no longer registered in the global scope by default. In other words, as of PHP » 4.2.0 the PHP directive register_globals is off by default in php.ini. The preferred method of accessing these values is via the superglobal arrays mentioned above. Older scripts, books, and tutorials may rely on this directive being on. If it were on, for example, one could use $id from the URL http://www.example.com/foo.php?id=42. Whether on or off, $_GET['id'] is available.
What's next?
http://talks.php.net/中文字的substr
$text = $_POST['name'];
$text1 = mb_substr($text,0,1);
$text2 = mb_substr($text,1,1);
$text3 = mb_substr($text,2,1);
PHP 5 Form Validation
| Field | Validation Rules |
|---|---|
| Name | Required. + Must only contain letters and whitespace |
| Required. + Must contain a valid email address (with @ and .) | |
| Website | Optional. If present, it must contain a valid URL |
| Comment | Optional. Multi-line input field (textarea) |
| Gender | Required. Must select one |
Text Fields
The name, email, and website fields are text input elements, and the comment field is a textarea. The HTML code looks like this:
Name: <input type="text" name="name">
E-mail: <input type="text" name="email">
Website: <input type="text" name="website">
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
Radio Buttons
The gender fields are radio buttons and the HTML code looks like this:
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
The Form Element
The HTML code of the form looks like this:
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Big Note on PHP Form Security
The $_SERVER["PHP_SELF"] variable can be used by hackers!
If PHP_SELF is used in your page then a user can enter a slash (/) and then some Cross Site Scripting (XSS) commands to execute.
 | Cross-site scripting (XSS) is a type of computer security vulnerability typically found in Web applications. XSS enables attackers to inject client-side script into Web pages viewed by other users. |
|---|
Assume we have the following form in a page named "test_form.php":
<form method="post" action="<?php echo $_SERVER["PHP_SELF"];?>">
Now, if a user enters the normal URL in the address bar like "http://www.example.com/test_form.php", the above code will be translated to:
<form method="post" action="test_form.php">
Validate Form Data With PHP
The first thing we will do is to pass all variables through PHP's htmlspecialchars() function.
When we use the htmlspecialchars() function; then if a user tries to submit the following in a text field:
<script>location.href('http://www.hacked.com')</script>
- this would not be executed, because it would be saved as HTML escaped code, like this:
<script>location.href('http://www.hacked.com')</script>
The code is now safe to be displayed on a page or inside an e-mail.
We will also do two more things when the user submits the form:
- Strip unnecessary characters (extra space, tab, newline) from the user input data (with the PHP trim() function)
- Remove backslashes (\) from the user input data (with the PHP stripslashes() function)
The next step is to create a function that will do all the checking for us (which is much more convenient than writing the same code over and over again).
We will name the function test_input().
Now, we can check each $_POST variable with the test_input() function, and the script looks like this:
Example Explained
<html>
<head>
</head>
<body>
<?php
// define variables and set to empty values
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$name = test_input($_POST["name"]);
$email = test_input($_POST["email"]);
$website = test_input($_POST["website"]);
$comment = test_input($_POST["comment"]);
$gender = test_input($_POST["gender"]);
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name">
<br><br>
E-mail: <input type="text" name="email">
<br><br>
Website: <input type="text" name="website">
<br><br>
Comment: <textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<br><br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
echo "<h2>Your Input:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>
Reference : http://www.w3schools.com/php/php_form_validation.asp Reference : http://php.net/manual/en/tutorial.php
