Retaining values across POST in a VERY basic php form
I'm going through a very basic php tutorial and am creating a calculator so I can get the hang of $_GET, $_POST and some general syntax.
I created a very basic php function calc(); in a php file called functionadvanced.php. All it does is take 2 numbers, an operator, does the math and spits out the results (like I said, very basic tutorial). The function works so I won't post the code.
I have another php file called calc.php that has my form for my calculator. Here's the code:
<?php
include "functionadvanced.php";
$number1 = $_POST['num1'];
$number2 = $_POST['num2'];
$operator = $_POST['op'];
?>
<html>
<body>
<form action='calc.php' method='POST'>
<input type='textbox' name='num1' value="<?php echo $_GET['$number1']; ?>"/>
<select name="op" selected="<?php echo $_GET['$operator']; ?>">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
<input type='textbox' name='num2' value="<?php echo $_GET['$number2']; ?>"/>
<input type='submit' value='=' />
<input type='text' name='result' value="<?php echo calc($number1,$number2,$operator); ?>" />
</form>
</body>
</html>
The form actually works, and shows the correct value that the cal开发者_JAVA技巧c function spits out, but when the page posts back it doesn't keep the posted back values in the fields. I thought I was suppose to use a $_GET to grab the values posted in the $_POST?
$_GET refers to information passed in the query string (index.php?id=123 gives $_GET['id'] = '123'), while $_POST is for form info. These correspond roughly (but not exactly) to the matching http request methods.
So you want to use $_POST again, or just use the variables you've already read from $_POST (like $number1).
NOTE: I know this is just a learning process, but this naive approach is vulnerable to XSS, so read up on that before going live with anything important...
why use $_GET when you have grabbed the values form $_POST? you just need to use them. and should also add defaults
<?php
include "functionadvanced.php";
$number1 = isset($_POST['num1'])?$_POST['num1']:0;
$number2 = isset($_POST['num2'])?$_POST['num2']:0;
$operator = isset($_POST['op'])?$_POST['op']:'+';
?>
<html>
<body>
<form action='calc.php' method='POST'>
<input name='num1' value="<?php echo $number1; ?>"/>
<select name="op" selected="<?php echo $operator; ?>">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
<input name='num2' value="<?php echo $number2; ?>"/>
<input type='submit' value='=' />
<input name='result' value="<?php echo calc($number1,$number2,$operator); ?>" />
</form>
</body>
</html>
also, there is no type="textbox", only text which is default. if you need a text box, you should use
加载中,请稍侯......
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