check input value after post

Question

I have test code

$chatText = "Hello world :D";

$chatText = str_replace(":D","<img src='happy.jpg' width='20' height='20' alt='Big Smile' />",$chatText);

echo $chatText;

basically what it does is replace the :D with an image. What I actually wanted to do is after clicking submit from a <textarea> -replace input value i.e emoticons (image) after post. How do I check user's input value to check to see if they have type these characters for example

":-)"

exactly as you do above but you have to put a post check in first so it only does the replacement if there's been a post. — Dave, Apr 26 '13 at 14:27
http://stackoverflow.com/questions/8829848/emoticon-replacement-php — Mudassir Hasan, Apr 26 '13 at 14:30

score 1 · Accepted Answer · edited May 23 '17 at 12:04

1

No need to check as str_replace will replace everything it matches, only check if the post isn't empty.

<?php
if($_POST['textarea_name']!=""){
    $text = $_POST['textarea_name'];
    $chatText = str_replace(":D","<img src='happy.jpg' width='20' height='20' alt='Big Smile' />",$text);
    echo $chatText;
}
?>

Check this out for more detailed replacement using arrays;

Emoticon Replacement - PHP

edited May 23 '17 at 12:04

Community

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answered Apr 26 '13 at 14:28

Dom

7,135
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Always use `htmlspecialchars` when outputting user contents to a web page to prevent XSS. – Marcel Korpel Apr 26 '13 at 14:29
But he's echoing out an image tag, that would turn all < into < and > into > which would render the image tag as normal text... – Dom Apr 26 '13 at 14:31
Then use `hmtlspecialchars` *before* the replacement takes place. – Marcel Korpel Apr 26 '13 at 14:33
@Dom `$chatText = str_replace(":D","",htmlspecialchars($text));` – Ejaz Apr 26 '13 at 14:33
But what about this smiley -> `:> - big grin` ? That would become :> and wouldn't be picked up by the script. – Dom Apr 26 '13 at 14:35
1

Then replace `:>` with an image. – Marcel Korpel Apr 26 '13 at 14:37
or better `$chatText = str_replace(htmlspecialchars(":D"),"",htmlspecialchars($text));` to maintain readability – Ejaz Apr 26 '13 at 14:39
@ejay: Fair enough, but in an array with hundreds(?) of emoticons, would it be worthwhile or efficient to do an array walk with htmlspecialchars? – Dom Apr 26 '13 at 14:42
If you've hundreds of emoticons in array then you can compromise readability over performance :) – Ejaz Apr 26 '13 at 14:49

score 1 · Answer 2 · answered Apr 26 '13 at 14:30

Something like the following would work correctly for you,

foreach ($_POST as $k=>$v) {
    $_POST[$k] = str_replace(":D","<img src='happy.jpg' width='20' height='20' alt='Big Smile' />",$v);
}

That would simply process and $_POST values submitted, in which what i'm gathering is you're using a chat box, so it should only process such message box, Thus meaning it will replace and :D characters within these text boxes.

check input value after post

2 Answers2