Тег <label></label>

Этот тег определяет метку для элемента.

Аргумент	Значение
for	element_id
form	form_id

index.php

<?php
class Symbol {
private $a = null;
private $b = null;
private $symbol = null;
function __construct($arg0, $arg1, $arg2) {
$this->a = $arg0;
$this->b = $arg1;
$this->symbol = $arg2;
}
function getA() {
return $this->a;
}
function getB() {
return $this->b;
}
function Result() {
switch($this->symbol) {
case '+' :
echo $this->a, ' + ', $this->b, ' = ', ($this->a + $this->b), '<br />';
break;
case '-' :
echo $this->a, ' - ', $this->b, ' = ', ($this->a - $this->b), '<br />';
break;
case '*' :
echo $this->a, ' * ', $this->b, ' = ', ($this->a * $this->b), '<br />';
break;
case '/' :
if($this->b == 0) {
echo 'You can not divide by zero!<br />';
}
else {
echo $this->a, ' / ', $this->b, ' = ', ($this->a / $this->b), '<br />';
}
break;
case '%' :
if((int)$this->b == 0) {
echo 'You can not divide by zero!<br />';
}
else {
echo (int)$this->a, ' % ', (int)$this->b, ' = ', ((int)$this->a % (int)$this->b), '<br />';
}
break;
}
}
}
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
</head>
<body>
<?php
if($_SERVER['REQUEST_METHOD'] == 'POST') {
$S = new Symbol((float)$_POST['a'], (float)$_POST['b'], $_POST['symbol']);
$a = $S->getA();
$b = $S->getB();
if($_REQUEST['clear']) {
$a = null;
$b = null;
}
}
?>
<form action="<?php echo $_SERVER['PHP_SELF'] ?>" method="post">
<input type="text" name="a" value="<?php echo $a; ?>" />
 
<label>Enter a value</label>
<br />
<br />
<input type="text" name="b" value="<?php echo $b; ?>" />
 
<label>Enter a value</label>
<br />
<br />
<select name="symbol">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
<option value="%">%</option>
</select>
 
<label>Select an arithmetic symbol + - * / %</label>
<br /><br /><br /><br /><br /><br />
<input type="submit" name="perform" value="Perform" /> 
  
<input type="submit" name="clear" value="   Clear   " />
<br />
<br />
</form>
<?php
if($_SERVER['REQUEST_METHOD']=='POST' && $_REQUEST['perform'] && !$_REQUEST['clear']) {
$S->Result();
}
else {
echo null;
}
?>
<script>
$(document).ready(function() {
$("select").css({"width": "141px", "text-align": "center"});
$("input").css({"text-align": "center"});
});
</script>
</body>
</html>

<?php
class Symbol {
private $a = null;
private $b = null;
private $symbol = null;
function __construct($arg0, $arg1, $arg2) {
$this->a = $arg0;
$this->b = $arg1;
$this->symbol = $arg2;
}
function getA() {
return $this->a;
}
function getB() {
return $this->b;
}
function Result() {
switch($this->symbol) {
case '+' :
echo $this->a, ' + ', $this->b, ' = ', ($this->a + $this->b), '<br />';
break;
case '-' :
echo $this->a, ' - ', $this->b, ' = ', ($this->a - $this->b), '<br />';
break;
case '*' :
echo $this->a, ' * ', $this->b, ' = ', ($this->a * $this->b), '<br />';
break;
case '/' :
if($this->b == 0) {
echo 'You can not divide by zero!<br />';
}
else {
echo $this->a, ' / ', $this->b, ' = ', ($this->a / $this->b), '<br />';
}
break;
case '%' :
if((int)$this->b == 0) {
echo 'You can not divide by zero!<br />';
}
else {
echo (int)$this->a, ' % ', (int)$this->b, ' = ', ((int)$this->a % (int)$this->b), '<br />';
}
break;
}
}
}
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
</head>
<body>
<?php
if($_SERVER['REQUEST_METHOD'] == 'POST') {
$S = new Symbol((float)$_POST['a'], (float)$_POST['b'], $_POST['symbol']);
$a = $S->getA();
$b = $S->getB();
if($_REQUEST['clear']) {
$a = null;
$b = null;
}
}
?>
<form action="<?php echo $_SERVER['PHP_SELF'] ?>" method="post">
<input type="text" name="a" value="<?php echo $a; ?>" />
 
<label>Enter a value</label>
<br />
<br />
<input type="text" name="b" value="<?php echo $b; ?>" />
 
<label>Enter a value</label>
<br />
<br />
<select name="symbol">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
<option value="%">%</option>
</select>
 
<label>Select an arithmetic symbol + - * / %</label>
<br /><br /><br /><br /><br /><br />
<input type="submit" name="perform" value="Perform" /> 
  
<input type="submit" name="clear" value="   Clear   " />
<br />
<br />
</form>
<?php
if($_SERVER['REQUEST_METHOD']=='POST' && $_REQUEST['perform'] && !$_REQUEST['clear']) {
$S->Result();
}
else {
echo null;
}
?>
<script>
$(document).ready(function() {
$("select").css({"width": "141px", "text-align": "center"});
$("input").css({"text-align": "center"});
});
</script>
</body>
</html>