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How do I allow only numbers in a text field?

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How do I allow only numbers in a text field?, DoI use ereg?
alyis
30 Sep, 2008 - 07:08 PM
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I need to allow users to only be able to submit numbers into a text field and if they submit anything else it needs to strip all other characters be it letters or symbols. If someone could help me with this it would be very much apprecaited...because as of right now a user can enter + signs on both side of a number like so, +10000+, and it will submit it and send that amount of money even if the user does not have that much.


CODE
<?php
include 'header.php';

if($_POST['sendmoney'] != ""){
  $money_person = new User($_POST['theirid']);

  if($user_class->money >= $_POST['amount'] && $_POST['amount'] > 0 && $user_class->id != $money_person->id){
    $newmoney = $user_class->money - $_POST['amount'];
    $result = mysql_query("UPDATE `grpgusers` SET `money` = '".$newmoney."' WHERE `id`='".$_SESSION['id']."'");

    $newmoney = $money_person->money + $_POST['amount'];
    $result = mysql_query("UPDATE `grpgusers` SET `money` = '".$newmoney."' WHERE `id`='".$_POST['theirid']."'");
    echo "You have successfully transferred $".$_POST['amount']." to ".$money_person->formattedname.".";
    Send_Event($user_points->id, "You have been sent $".$_POST['amount']." from ".$user_class->formattedname);
  } else {
    echo "You don't have enough money to do that!";
  }
}
?>

<div class="content"><u>Send Money</u><br>
<form name='login' method='post' action='sendmoney.php'>
  <p>&nbsp;</p>
  <table border='0' cellpadding='0' cellspacing='0'>
    <tr>
      <td width='35%' height='27'>Amount Of Money</td>
      <td width='65%'>
        <input name='amount' type='text' size='22'>
        </td>
    </tr>
        <tr>
      <td width='35%' height='27'>User ID</td>
      <td width='65%'>
        <input name='theirid' type='text' size='22' value='<? echo $_GET['person'] ?>'>
        </td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td>
        <input type='submit' name='sendmoney' value='Send Money'>
        </td>
    </tr>
  </table>
</form>
</div>


<?php
include 'footer.php';
?>
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grimpirate
RE: How Do I Allow Only Numbers In A Text Field?
30 Sep, 2008 - 08:46 PM
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CODE
$length = strlen($_POST['amount']);
for($i = 0; $i < $length; $i++){
$numbers = '';
$temp = ord(substr($_POST['amount'], $i, 1));
if($temp > 47 && $temp < 58)
$numbers .= chr($temp);
}
if(strlen($numbers) == 0) $numbers = 0;


This post has been edited by grimpirate: 30 Sep, 2008 - 08:47 PM
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alyis
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 03:34 AM
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Could you please explain your as to help me learn what I need to do....
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pemcconnell
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 03:46 AM
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*EDIT*

I would change the second and third lines from this:

CODE

for($i = 0; $i < $length; $i++){
$numbers = '';


to this:

CODE

$numbers = '';
for($i = 0; $i < $length; $i++){


As $numbers was being reset to '' in every instance of the loop.

*END EDIT*

To explain what grim's code does, it loops through the amount entered, checking each number / letter.

$temp is the ASCII value of the individual character of each number/letter in amount. e.g.

4734556
$temp on the first loop is the ASCII value of 4, 7 on the second loop, 3 on the third loop, 4 on the 4th etc.

So, if $temp is between 48 and 57, it is concidered a number (I'm assuming that 48 - 57 is the ASCII range of 0 - 9, don't know the ASCII values of the top of my head)

If it is in this range then it is a number, so it is appended to the variable $numbers.

So, if you where to enter this as the amount:

54asd65asd45

You would get 546545 as the $numbers value.

All in all a nice function that i think I'll be adding to my library, thanks grim smile.gif

This post has been edited by pemcconnell: 1 Oct, 2008 - 04:52 AM
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alyis
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 03:52 AM
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Thankyou pem and grim. This helps me alot with my game. IF anyone else has any other ways of doing this feel free to share them.

This post has been edited by alyis: 1 Oct, 2008 - 03:53 AM
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pemcconnell
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 04:55 AM
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I added grims code into a function with the tiny change i mentioned in my last post:

CODE

function getNumbersOnly($value){
    $numbers = '';
    for($i = 0; $i < strlen($value); $i++){
        $temp = ord(substr($value, $i, 1));
        if($temp > 47 && $temp < 58){
            $numbers .= chr($temp);
        }
    }
    return $numbers;
}


Full credit to grimpirate for the function.

This post has been edited by pemcconnell: 1 Oct, 2008 - 05:22 AM
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alyis
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 05:15 AM
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I am not quite sure how i should be implementing this into my code..I am very new to PHP. Can I also see an example of how I would only allow numbers using ereg() statements? And also how to replace anything eneteredinto the field such as +123123+ to remove the + and + fromt he outsides and only keep the 123123?
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pemcconnell
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 05:28 AM
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Here is an example of the code:

CODE

function getNumbersOnly($value){
    $numbers = '';
    for($i = 0; $i < strlen($value); $i++){
        $temp = ord(substr($value, $i, 1));
        if($temp > 47 && $temp < 58){
            $numbers .= chr($temp);
        }
    }
    return $numbers;
}

$amount = getNumbersOnly($_POST['amount']);

?>


So if the user has entered +123456+ into the 'amount' field and posted the form, this line:

CODE

$amount = getNumbersOnly($_POST['amount']);


would strip any non-numbers from the data, meaning the code would read:

CODE

$amount = 123456;


*Again, all credit should go to grim for that

To use regular expressions to validate if a character is in the string, you could use:

CODE

$text = "mixedcharacters012345&../@";



if (ereg('[^A-Za-z0-9]', $text)) {

  echo "This contains characters other than just numbers";

}

else {

  echo "This contains only numbers";    

}


Taken from this site
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akozlik
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 05:29 AM
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Here's some Javascript that you can include for your form:

How Can I Use Javascript to Allow Only Numbers to be Entered in a Textbox?

Wow, that's a long title.

You could use that on the front end of the site, to limit what can be entered into the form. Then after the form is submitted you could use PHP to double check that the string only contains numbers using any of the methods that have been given to you.

It's very important to double check with PHP, as Javascript can easily be beat.

Good luck!
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CTphpnwb
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 05:35 AM
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QUOTE(grimpirate @ 30 Sep, 2008 - 09:46 PM) *

CODE
$length = strlen($_POST['amount']);
for($i = 0; $i < $length; $i++){
$numbers = '';
$temp = ord(substr($_POST['amount'], $i, 1));
if($temp > 47 && $temp < 58)
$numbers .= chr($temp);
}
if(strlen($numbers) == 0) $numbers = 0;



I would add a test at the end to see if $numbers == $_POST['amount']. That's because if somebody enters something like "99 Main Street", this will result in $numbers = 99. It's likely that the user in such a case will have typed the information in the wrong field, and the intended number for this field is either missing completely or entered elsewhere.

If you confirm that $numbers == $_POST['amount'] then at least you know that they meant to enter a number.
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akozlik
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 05:39 AM
Post #11

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Has everybody forgotten about the built in function is_numeric()?

php

<?php
$number = $_POST['amount'];
$length = strlen($number);
for ($i=0; $i<$length; $i++)
{
    if ( !is_numeric($number[$i]) ) $number[$i] = '';
}
?>


Seems a bit simpler. If you can avoid regular expressions, you should.

This actually brings up a good point. When looking to complete a specific tasks, check the documentation on php.net and see if there's a prebuilt function. Often, there are already solutions for what you're trying to find.

Here's where the function description is. Check the left side column for a list of other is_* functions.

Hope that helps.

This post has been edited by akozlik: 1 Oct, 2008 - 05:42 AM
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alyis
RE: How Do I Allow Only Numbers In A Text Field?
1 Oct, 2008 - 05:46 AM
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Thank you very much penn for that explantion. It helped me alot I will try to use that right now and tell you how it works for me. Thankyou everyone else as well for the help with this bug.
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