Working with strings and variables from html forms to php

Question

I have been struggling with a problem working in both html and php. in my html, i have a form tag that includes:

<input type="text" name="car1" size="4" value="" /> car1

In my php, i have this:

$car1 = 'my favorite car is ' . $_POST['car1'];
echo $car1;

I am trying to figure out a way so that when the user does not input anything into the car1 field in html, echo $car1; will print nothing or blank but when the user does input something, $car1 will echo my favorite car is $car1.

I tried using if(empty() and if(isset() but i am having issues to make it work for some reason.

Any ideas to do this properly? thanks for the help!

user557846 · Accepted Answer · 2011-02-25 02:01:09Z

1

if(!empty($_POST['car1'])){
$car1 = 'my favorite car is ' . $_POST['car1'];
echo $car1;
}

answered Feb 25, 2011 at 2:01

user557846

Sign up to request clarification or add additional context in comments.

3 Comments

David Wolever Over a year ago

The only minor problem with this is that empty("0") will evaluate to true… So if the value of car1 is "0", the $car1 = ... won't get evaluated.

Kevin Jung Over a year ago

I somehow didnt have that dot between the string and the variable! thanks for the help!

user557846 Over a year ago

@David i know this, the manual says this, but for this instance, as there is no car called "0" it seemed like a valid responce, i used the context provided by the poster to decide the appropriate approach, which is how things should be written.

David Wolever · Accepted Answer · 2011-02-25 02:00:30Z

0

Try:

if ($_POST["car1"] !== "") {
    $car1 = "my favourite …";
} else {
    $car1 = "";
}

answered Feb 25, 2011 at 2:00

David Wolever

156k94 gold badges365 silver badges513 bronze badges

2 Comments

deceze Over a year ago

The only minor problem with your answer is that it will throw notices if $_POST['car1'] does not exist. :)

David Wolever Over a year ago

Ah, very true! Unless, of course, you're pro enough to be rolling with error_reporting = 0.

deceze · Accepted Answer · 2011-02-25 02:13:37Z

0

As simple as:

if (!empty($_POST['car1'])) {
    echo 'my favorite car is ' . htmlentities($_POST['car1']);
}

See here which values are regarded as empty. If you want more control, use something like:

if (isset($_POST['car1']) && $_POST['car1'] !== '')

You should

always check whether keys in $_POST are !empty or isset before using them
always HTML escape user supplied data for output

use labels:

<input type="text" name="car1" size="4" id="car1Input" value="" />
<label for="car1Input">car1</label>

edited Feb 25, 2011 at 2:13

answered Feb 25, 2011 at 2:01

deceze♦

525k89 gold badges806 silver badges954 bronze badges

2 Comments

David Wolever Over a year ago

As I noted on Dagon's answer: the only minor problem with this is that empty("0") will evaluate to true… So if the value of car1 is "0", the $car1 = ... won't get evaluated.

deceze Over a year ago

@David Sure, in that case use isset instead. Depends on what values you regard as "empty".

ThorDozer · Accepted Answer · 2011-02-25 02:25:03Z

0

if(isset($_POST["car1"]))
    $car1 = "my favorite car is $_POST["car1"]";
else 
    $car1 = "";
return $car1 //if function or
echo $car1; //if general

edited Feb 25, 2011 at 2:25

answered Feb 25, 2011 at 2:16

ThorDozer

1042 silver badges13 bronze badges

Collectives™ on Stack Overflow

Working with strings and variables from html forms to php

4 Answers 4

3 Comments

2 Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

3 Comments

2 Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related