radio button option posted to a backend php program

helen11 · June 30, 2012

I would like the radio button option from a html form posted to a backend php program along with a simple calculation, I can get the calculator to work but I cant get it to post the radio button value. Any help would be greatly appreciated.

<head>
<title></title>
</head>
<body>
<h1>Simple Calculator</h1>


<h2>Please Select an Option</h2>
<form method="post" action="calculation.php">
<div>
<input type="radio" name="calcu" value="Highest"> Highest<br>
<input type="radio" name="calcu" value="Lowest" checked> Lowest<br>
<input type="radio" name="calcu" value="Average"> Average<br>
<input type="radio" name="calcu" value="Sort in ascending order"> Sort in ascending order<br>
</div>
</form>

<h2>Insert five numbers in the form and hit submit button</h2>

<form method="post" action="calculation.php">

<p>Value 1: <input type="text" name="val1" size="10"></p>
<p>Value 2: <input type="text" name="val2" size="10"></p>
<p>Value 3: <input type="text" name="val3" size="10"></p>
<p>Value 4: <input type="text" name="val4" size="10"></p>
<p>Value 5: <input type="text" name="val5" size="10"></p>
<p>Calculation:<br>
<input type="radio" name="calc" value="add"> add<br>
<input type="radio" name="calc" value="subtract">  subtract<br>
<input type="radio" name="calc" value="multiply"> multiply<br>
<input type="radio" name="calc" value="divide"> divide</p>
<p><input type="submit" name="submit" value="Calculate"></p>
</form>
</body>
</html>

<head>
<title>Simple Calculator</tite>
</head>
<body>
<?php

if (($_POST[val1] == "") || ($_POST[val2] == "") || ($_POST[val3] == "") || ($_POST[val4] == "") || ($_POST[val5] == "") || ($_POST[calc] =="")) {
  header("Location: form.html");
  exit;
}
if ($_POST[calc] == "add") {
  $result = $_POST[val1] + $_POST[val2] + $_POST[val3] + $_POST[val4] + $_POST[val5];
} else if ($_POST[calc] == "subtract") {
  $result = $_POST[val1] - $_POST[val2] - $_POST[val3] - $_POST[val4] - $_POST[val5];
} else if ($_POST[calc] == "multiply") {
  $result = $_POST[val1] * $_POST[val2] * $_POST[val3] * $_POST[val4] * $_POST[val5];
} else if ($_POST[calc] == "divide") {
  $result = $_POST[val1] / $_POST[val2] / $_POST[val3] / $_POST[val4] / $_POST[val5];
}
echo "<title>Calculation Result</title>";
echo "<p>The result of the calculation is: $result</p>";
echo "<p><a href=\"form.html\" target=\"_self\">Do Another</a></p>";
?>



</body>
</html>

Pikachu2000 · June 30, 2012

See if calc is an element in the $_POST array.

echo '<br>Start POST Array:<pre>';
print_r($_POST);
echo '</pre>End POST array<br>';

And while developing, you should always have error reporting on. Do so by editing the proper php.ini file directives to:

error_reporting = -1

display_errors = On

Then restart Apache.

Barand · June 30, 2012

Also, all those $_POST indexes are string values and should be enclosed in quotes.

ie $_POST['val1'], $_POST['calc'] and not $_POST[val1], $_POST[calc]

helen11 · June 30, 2012

I'm not talking about the calculation text boxes that part works, when 5 numbers are put in the text boxes and calculated it returns the answer. What I want to know is how do I get the chosen radio button option posted to the backend php program?

DavidAM · June 30, 2012

Your radio buttons are in a separate FORM element. When you submit a form, only the elements in the FORM that contains the submit button are submitted.

helen11 · June 30, 2012

Ok thanks for that I have only one form element now. Do you know how i would post the selected radio button to the backend php program?

Barand · June 30, 2012

It should be in $_POST['calcu'] as the code that Pikachu gave you should confirm

helen11 · June 30, 2012

It won't work for me and i'm ready to pull my hair out

darkfreaks · July 1, 2012

all your $_POST values need to be in double or single quotes.

IE instead of $_POST[calc] it should be $_POST['calc']

do that to all the other post values.

Pikachu2000 · July 1, 2012

See if calc is an element in the $_POST array.
echo '<br>Start POST Array:<pre>';
print_r($_POST);
echo '</pre>End POST array<br>';
And while developing, you should always have error reporting on. Do so by editing the proper php.ini file directives to:

error_reporting = -1

display_errors = On

Then restart Apache.

Did you do this? Was 'calc' an element in the $_POST array? Did you compare the error notice to what was actually in the $_POST array?

Drummin · July 1, 2012

Sounds like homework.

In any case, your two radio button sets need to processed as either/or because you can't for example show the highest while also getting the sum. For this reason, I would name them all the same. You have radio buttons above and below text inputs and so to make the display less confusing, I would place them all at the top and label them as a group side-by-side. A few floating divisions should do the job.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Simple Calculator</title>
</head>
<body>
<h1>Simple Calculator</h1>
<h2>Please Select an Option</h2>
<form method="post" action="calculation.php">
	<div style="float:left;">
		<div style="float:left; padding-right:10px">
			<h3>Sort Options</h3>
			<input type="radio" name="calc" value="Highest" /> Highest<br />
			<input type="radio" name="calc" value="Lowest" /> Lowest<br />
			<input type="radio" name="calc" value="Average" /> Average<br />
			<input type="radio" name="calc" value="Sort in ascending order" /> Sort in ascending order<br />
		</div>
		<div style="float:left;">
		<h3>Calculation Options</h3>
			<input type="radio" name="calc" value="add" /> add<br />
			<input type="radio" name="calc" value="subtract" />  subtract<br />
			<input type="radio" name="calc" value="multiply" /> multiply<br />
			<input type="radio" name="calc" value="divide" /> divide<br />
		</div>
	</div>
	<div style="float:left; clear:both;">
		<h2>Insert five numbers in the form and hit submit button</h2>

		<p>Value 1: <input type="text" name="val1" size="10" /></p>
		<p>Value 2: <input type="text" name="val2" size="10" /></p>
		<p>Value 3: <input type="text" name="val3" size="10" /></p>
		<p>Value 4: <input type="text" name="val4" size="10" /></p>
		<p>Value 5: <input type="text" name="val5" size="10" /></p>
		<p><input type="submit" name="submit" value="Calculate" /></p>
	</div>
</form>
</body>
</html>

For processing, it's better to use

if (empty($_POST['val1'])

rather than

if ($_POST[val1] == "")

Also note, as already mentioned how the $_POST keys are in single quotes, i.e. ['val1'].

When dealing with radio buttons, unless you've added a default selection as blank...

<input type="radio" name="calc" value="" checked="checked" /> Choose

...then checking for blank is pointless.

$_POST[calc] ==""

Instead check if the value isset().

if (isset($_POST['calc'])){

header() should always be called before anything is sent to the browser, ex. <head> etc. and in general it's a good practice to always do any post-processing before output, so get in the habit of setting up your pages this way. In fact in a case like this project, I would put processing above <html> on the same page and make the form fields sticky (echo post values back) so it the user forgets to make a selection, the values are still in the form and you can display a message like "Please select a processing option".

As far as the sorting options, I think adding posted values to an array then sorting is the way to go.

Because I have processing above <body> tag, I will format result output as a variable and echo within body.

So in any case, here's my version.

<?php
if (empty($_POST['val1']) || empty($_POST['val2']) || empty($_POST['val3']) || empty($_POST['val4']) || empty($_POST['val5'])) {
  header("Location: form.html");
  exit;
}
if (!isset($_POST['calc'])){
  header("Location: form.html");
  exit;
}else{
if (isset($_POST['calc'])){
	if ($_POST['calc'] == "add") {
	  $result = $_POST['val1'] + $_POST['val2'] + $_POST['val3'] + $_POST['val4'] + $_POST['val5'];
	} elseif ($_POST['calc'] == "subtract") {
	  $result = $_POST['val1'] - $_POST['val2'] - $_POST['val3'] - $_POST['val4'] - $_POST['val5'];
	} elseif ($_POST['calc'] == "multiply") {
	  $result = $_POST['val1'] * $_POST['val2'] * $_POST['val3'] * $_POST['val4'] * $_POST['val5'];
	} elseif ($_POST['calc'] == "divide") {
	  $result = $_POST['val1'] / $_POST['val2'] / $_POST['val3'] / $_POST['val4'] / $_POST['val5'];
	} elseif ($_POST['calc'] == "Highest") {
		  $total= array();
		  $total[] =$_POST['val1'];
		  $total[] =$_POST['val2'];
		  $total[] =$_POST['val3'];
		  $total[] =$_POST['val4'];
		  $total[] =$_POST['val5']; 
		  $result = max($total);
	} elseif ($_POST['calc'] == "Lowest") {
		  $total= array();
		  $total[] =$_POST['val1'];
		  $total[] =$_POST['val2'];
		  $total[] =$_POST['val3'];
		  $total[] =$_POST['val4'];
		  $total[] =$_POST['val5']; 
		  $result = min($total);
	} elseif ($_POST['calc'] == "Average") { 			  
		  $result = (($_POST['val1'] + $_POST['val2'] + $_POST['val3'] + $_POST['val4'] + $_POST['val5'])/5);
	} elseif ($_POST['calc'] == "Sort in ascending order") {
		  $numbers= array();
		  $numbers[] =$_POST['val1'];
		  $numbers[] =$_POST['val2'];
		  $numbers[] =$_POST['val3'];
		  $numbers[] =$_POST['val4'];
		  $numbers[] =$_POST['val5'];
		  asort($numbers); 
		  $result = implode(', ',$numbers);
	}
}
}
$display ="";
$display .="<p>The result of the calculation is: $result</p>";
$display .="<p><a href=\"form.html\" target=\"_self\">Do Another</a></p>";
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Calculation Result</title>
</head>
<body>
<?php 
if (isset($display)){ echo "$display"; }
?>
</body>
</html>

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radio button option posted to a backend php program

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