PHP Example
Screen shot
PHP Script to Calculate Resturant bill
<?php
if(isset($_POST[\'btn\']))
{
if(isset($_POST[\'chk1\']))
{
    $one=$_POST[\'chk1\'];
    $t_c=$_POST[\'coffee\']*$_POST[\'Coffee_rate\'];
}
else
{
$t_c=0;
$one=0;
}
if(isset($_POST[\'chk2\']))
{
    $two=$_POST[\'chk2\'];
    $t_cd=$_POST[\'cold_drink\']*$_POST[\'Cold_drink_rate\'];
}
else
{
$t_cd=0;
$two=0;
}
if(isset($_POST[\'chk3\']))
{
    $three=$_POST[\'chk3\'];
    $t_p=$_POST[\'pizza\']*$_POST[\'Pizza_rate\'];
    }
else
    {
$t_p=0;
$three=0;
}
if(isset($_POST[\'chk4\']))
{
    $four=$_POST[\'chk4\'];
    $t_t=$_POST[\'tea\']*$_POST[\'Tea_rate\'];
    }
else
{
$t_t=0;
$four=0;
}
if(isset($_POST[\'chk5\']))
{
    $five=$_POST[\'chk5\'];
    $t_w=$_POST[\'water\']*$_POST[\'Water_rate\'];
}
    else
    {
    $t_w=0;
    $five=0;
    }
$result=$t_c+$t_cd+$t_p+$t_t+$t_w;   
}
?>
<html>
<head>
<title></title>
</head>
<body>
<form name=\"frm\" action=\"\" method=\"post\">
<table border=\"1\">
<th>Drinks</th>
<th>Price</th>
<th>Quantity</th>
<th>status</th>
<tr>
<td>1 : Coffee </td>
<td><input type=\"hidden\" name=\"Coffee_rate\" value=\"5\" />5$</td>
<td><input type=\"text\" name=\"coffee\" size=\"5\" /></td>
<td><input type=\"checkbox\" name=\"chk1\" value=\"coffee\" /></td>
</tr>
<tr>
<td>2 : Cold drinks </td>
<td><input type=\"hidden\" name=\"Cold_drink_rate\" value=\"10\" />10$</td>
<td><input type=\"text\" name=\"cold_drink\" size=\"5\" /></td>
<td><input type=\"checkbox\" name=\"chk2\" value=\"cold drinks\" />
</td>
</tr>
<tr>
<td>3 : Pizza </td>
<td><input type=\"hidden\" name=\"Pizza_rate\" value=\"15\" />15$</td>
<td><input type=\"text\" name=\"pizza\" size=\"5\" /></td>
<td><input type=\"checkbox\" name=\"chk3\" value=\"pizza\" />
</td>
</tr>
<tr>
<td>4 : Tea </td>
<td><input type=\"hidden\" name=\"Tea_rate\" value=\"5\" size=\"4\" />5$</td>
<td><input type=\"text\" size=\"5\" name=\"tea\" /></td>
<td><input type=\"checkbox\" name=\"chk4\" value=\"tea\" />
</td>
</tr>
<tr>
<td>5 : Water </td>
<td><input type=\"hidden\" name=\"Water_rate\" value=\"5\" size=\"4\" />5$</td>
<td><input type=\"text\" size=\"5\" name=\"water\" /></td>
<td><input type=\"checkbox\" name=\"chk5\" value=\"water\" />
</td>
</tr>
<tr>
<td colspan=\"4\">
<?php
if(isset($_POST[\'chk1\']))
echo \"You have choosen \".$_POST[\'coffee\'] .\" \".$one.\"<br>\";
if(isset($_POST[\'chk2\']))
echo \"You have choosen \".$_POST[\'cold_drink\'] .\" \".$two.\"<br>\";
if(isset($_POST[\'chk3\']))
echo \"You have choosen \".$_POST[\'pizza\'] .\" \".$three.\"<br>\";
if(isset($_POST[\'chk4\']))
echo \"You have choosen \".$_POST[\'tea\'] .\" \".$four.\"<br>\";
if(isset($_POST[\'chk5\']))
echo \"You have choosen \".$_POST[\'water\'] .\" \".$five.\"<br>\";
?>
</td>
</tr>
<tr>
<td>Total amount</td>
<td colspan=\"3\"><input type=\"text\" name=\"\" value=\"<?php if(isset($result))echo \"please pay \".\"$ \".$result;else echo \"result here\";?>\" /></td>
</tr>
<tr>
<td align=\"center\" colspan=\"4\"><input type=\"submit\" name=\"btn\" value=\"click here\" /></td>
</tr>
</table>
</form>
</body>
</html>

You can download source code here