JavaScript - Limiting Text Typed Into A Form Text Box

I'm creating a page that calculates a number depending on what value is inputted into a text field. I need to create some javascript that updates this new calculated value and outputs it next to the input field. Anytime the user changes the number, it recalculates the value. My calculation is currently being produced by PHP, however if I need to, I can create javascript as well to recalculate these numbers.

My formulas for all 4 calculations are as follows:

First: Inputted Value * 10
Second: Inputted Value * 20
Third: Inputted Value / 2
Fourth: Inputted Value * 2

Here is my code I'm working with:

PHP Code:
<?php
session_start();
$username = $_SESSION['username'];

include_once('inc/connect.php');

$credquery = mysql_query("SELECT * FROM userstats WHERE username='$username'");
$row = mysql_fetch_assoc($credquery);

$credits = $row['credits'];
$bannercredits = $row['bannercredits'];
$textcredits = $row['textcredits'];

$sitetobanner = $_POST['sitetobanner'];
$sitetotext = $_POST['sitetotext'];
$bannertotext = $_POST['bannertotext'];
$texttobanner = $_POST['texttobanner'];

if (isset($sitetobanner)){

$bannerimp = round($_POST['bannerimp']);
    if ($bannerimp > 1){
        $s = "s";
    }
    if ($bannerimp <= $credits){
        $newcredits = $credits - $bannerimp;
        $newbannercredits = $bannerimp * 10;
        $totalbannercredits = $bannercredits + $newbannercredits;
        
        $updatebanner = mysql_query("UPDATE userstats SET credits='$newcredits', bannercredits='$totalbannercredits' WHERE username='$username'");
        
        $credits = $row['credits'];
        $bannercredits = $row['bannercredits'];
        $textcredits = $row['textcredits'];

        $convertedbanner = "You converted ".$bannerimp." credit".$s." into ".$newbannercredits." banner impressions";
        
    }
    else{
    if ($credits>1){
    $mycredits = $credits - 1;}
    $errorbanner = number_format($mycredits, 0, '.', '');

    }

}


if (isset($sitetotext)){

$textimp = round($_POST['textimp']);
    if ($textimp > 1){
        $s = "s";
    }
    if ($textimp <= $credits){
        $newcredits = $credits - $textimp;
        $newtextcredits = $textimp * 20;
        $totaltextcredits = $textcredits + $newtextcredits;
        
        $updatebanner = mysql_query("UPDATE userstats SET credits='$newcredits', textcredits='$totaltextcredits' WHERE username='$username'");
        
        $credits = $row['credits'];
        $bannercredits = $row['bannercredits'];
        $textcredits = $row['textcredits'];
        
        $convertedtext = "You converted ".$textimp." credit".$s." into ".$newtextcredits." text ad impressions";
        
    }
    else{
    
    if ($credits>1){
    $mycredits = $credits - 1;}
    $errortext = number_format($mycredits, 0, '.', '');
    
    }

}


if (isset($texttobanner)){

$texttobannerimp = round($_POST['texttobannerimp']);
    if ($texttobannerimp > 1){
        $s = "s";
    }

    if ($texttobannerimp <= $textcredits){
        if ($texttobannerimp>=2&&$texttobannerimp>""){
        $newcredits = $textcredits - $texttobannerimp;
        $newbannercredits = $texttobannerimp / 2;
        $totalbannercredits = $bannercredits + $newbannercredits;
        
        $updatebanner = mysql_query("UPDATE userstats SET textcredits='$newcredits', bannercredits='$totalbannercredits' WHERE username='$username'");
        
        $credits = $row['credits'];
        $bannercredits = $row['bannercredits'];
        $textcredits = $row['textcredits'];
        
        $convertedtextimp = "You converted ".$texttobannerimp." text ad impression".$s." into ".$newbannercredits." banner impressions";
        }
        else{
            $convertedtextimp = "You Hag";
        }
    }
    else{
    
    if ($textcredits>1){
    $mycredits = $textcredits - 1;}
    $errortextimp = number_format($mycredits, 0, '.', '');
    
    }
}


if (isset($bannertotext)){

$bannertotextimp = round($_POST['bannertotextimp']);
    if ($bannertotextimp > 1){
        $s = "s";
    }
    if ($bannertotextimp <= $bannercredits){
        $newcredits = $bannercredits - $bannertotextimp;
        $newtextcredits = $bannertotextimp * 2;
        $totaltextcredits = $textcredits + $newtextcredits;
        
        $updatebanner = mysql_query("UPDATE userstats SET bannercredits='$newcredits', textcredits='$totaltextcredits' WHERE username='$username'");
        
        $credits = $row['credits'];
        $bannercredits = $row['bannercredits'];
        $textcredits = $row['textcredits'];

        $convertedbannerimp = "You converted ".$bannertotextimp." banner impression".$s." into ".$newtextcredits." text impressions";
        
    }
    else{
    
    if ($bannercredits>1){
    $mycredits = $bannercredits - 1;}
    $errorbannerimp = number_format($mycredits, 0, '.', '');
    }
}



?>
<html>
<head>
<title>Convert Credits</title>
<script type="text/javascript" language="javascript">
function inputLimiter(e,allow) {
var AllowableCharacters = '';
if (allow == 'NumbersOnly'){AllowableCharacters='0123456789.';}

var k;
k=document.all?parseInt(e.keyCode): parseInt(e.which);
if (k!=13 && k!=8 && k!=0){
if ((e.ctrlKey==false) && (e.altKey==false)) {
return (AllowableCharacters.indexOf(String.fromCharCode(k))!=-1);
} else {
return true;
}
} else {
return true;
}
}

</script>
</head>
<body>
<h1>Convert Credits</h1><br />
Credits: <?php echo $credits; ?><br />
Banner Impressions: <?php echo $bannercredits; ?><br />
Text Ad Impressions: <?php echo $textcredits; ?><br />

<form action="convert.php" method="POST">
    <h3>Credits To Banner Impressions</h3>
    Convert <input type="text" name="bannerimp" id="NumbersOnly" onkeypress="return inputLimiter(event,'NumbersOnly')" value="<?php echo $errorbanner; ?>" onChange=""> credits into BLANK Banner Impressions! 
    <input type="submit" name="sitetobanner" value="Convert"><br />
    <?php echo $convertedbanner; ?>
</form>

<form action="convert.php" method="POST">
    <h3>Credits To Text Ad Impressions</h3>
    Convert <input type="text" name="textimp" id="NumbersOnly" onkeypress="return inputLimiter(event,'NumbersOnly')" value="<?php echo $errortext; ?>"> credits into BLANK Text Ad Impressions! 
    <input type="submit" name="sitetotext" value="Convert"><br />
    <?php echo $convertedtext; ?>
</form>

<form action="convert.php" method="POST">
    <h3>Text Ad To Banner Impressions</h3>
    Convert <input type="text" name="texttobannerimp" id="NumbersOnly" onkeypress="return inputLimiter(event,'NumbersOnly')" value="<?php echo $errortextimp; ?>"> Text Ad Impressions into BLANK Banner Impressions! 
    <input type="submit" name="texttobanner" value="Convert"><br />
    <?php echo $convertedtextimp; ?>
</form>

<form action="convert.php" method="POST">
    <h3>Banner To Text Ad Impressions</h3>
    Convert <input type="text" name="bannertotextimp" id="NumbersOnly" onkeypress="return inputLimiter(event,'NumbersOnly')" value="<?php echo $errorbannerimp; ?>"> Banner Impressions into BLANK Text Ad Impressions! 
    <input type="submit" name="bannertotext" value="Convert"><br />
    <?php echo $convertedbannerimp; ?>
</form>

</body>
</html>

As of right now I have a code that will work in IE but wont work in FireFox...go figure. Basically what I want to have happen is when you type in an area code it will provide an output in a predetermined area of the page.

For Example:

Input- 512

Output - Austin, TX

The code that I have doesn't work with firefox and I was just wondering if there was a code that would allow that to happen. Thanks!

well title says it all

i have a search form, and the default value is "enter text here"

when the user click the submit button, i would like to check if the value of my text input is "enter text here" and if it is, then don't submit the form (popup a warning or something)

how can i do that?

thanks a lot!

Hi,

I have a form with 9 text fields and a text area. What I want to do is replace the text in the text area depending on how many fields contain text. For example my text boxes are named 1 to 9, if the user enters text in the first five boxes I want the text area to auto fill with 'you have selected boxes 1 to 5' if the user selects all nine it will say 'you have selected 1 to 9', therefore, the user must complete the text boxes in order. I have it working with an onchange event but i have a button on the form to also auto fill the text boxes and it does not work if this is clicked.

Any help would be appreciated!

Hi all,

Thanks for reading. I'm having an issue trying to accomplish the following -

I have a text field (field1) already displayed on the HTML page. However, there's a link where you can add additional text fields to the page as well. When the link is clicked, the second text field is added successfully (field2), and when the link is clicked again, the third text field (field3) is added successfully. However, the third field does not add itself to the page, and the text for anything greater than a third field also isn't displayed after.

This obviously means that my "fields" variable is not working right, so I'm wondering, would anyone be able to assist me to help me get that variable processing correctly?

Code:

<script language="javascript">

fields = 1;

function addMore() {

if (fields = 1) {

document.getElementById('addedMore').innerHTML = "<input type='text' name='field2' size='25' /> <span>Field 2.</span>";

fields = 2;

} else if (fields = 2) {

document.getElementById('addedMore').innerHTML = "<input type='text' name='field3' size='25' /> <span>Field 3.</span>";
fields = 3;

} else {

document.getElementById('addedMore').innerHTML = "Only 3 fields are allowed.";
document.form.add.disabled=true;

}

}

</script>

Here is the code in my HTML -

Code:

<input type="text" name="field1" size="25" /> <span>Field 1.</span>
<div id="addedMore"></div>
<p class="addMore"><form name="add"><a onclick="addMore()">Add another field.</a></form></p>

Thank you very much.