how to disable special characters in a textbox/textarea?

**nebchill26** · 07-01-2008 10:02 PM

can anybody please show me how can i disable special characters in a textbox/textarea? im still not very skillful in javascript so i wanted to ask anyone to help me,tnx in advance

**Kor** · 07-02-2008 02:25 AM

Which special characters? Or maybe it is easier to specify which characters should be allowed. RegExp could be useful for this job

**nebchill26** · 07-02-2008 02:30 AM

i only want to allow 0-9 and a-z and ñ and Ñ,can you show me an example of what you suggested?tnx

**Kor** · 07-02-2008 02:49 AM

Code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta http-equiv="Content-Style-Type" content="text/css">
<meta http-equiv="Content-Script-Type" content="text/javascript">
<script type="text/JavaScript">
function valid(f) {
!(/^[A-z&#209;&#241;0-9]*$/i).test(f.value)?f.value = f.value.replace(/[^A-z&#209;&#241;0-9]/ig,''):null;
} 
</script>
</head>
<body><br>
<form id="myform" action="">
<input name="mytext" type="text" onkeyup="valid(this)" onblur="valid(this)">
</form>
</body>
</html>

**nebchill26** · 07-02-2008 02:57 AM

wow it worked! tnx your a life saver man,one thing though when i try the ñ and Ñ it still get deleted...

**Kor** · 07-02-2008 08:01 AM

In works for me. Well yes, I have no Spanish keyboard (thus I can not test onkeyup), but if I copy/paste the characters Ññ, they remain in the field. But it theory should work the same onkeyup as onblur.

What charset do you use? iso-8859-1 ?

**Declan1991** · 07-02-2008 02:07 PM

Maybe use the unicode versions?

Code:

function valid(f) {
f.value = f.value.replace(/[^a-z\u00D1\u00F10-9]*/ig,'');
}

I have no Spanish keyboard either, so I cannot check.

**jagh** · 09-05-2011 02:31 AM

How to disallow characters ñÑ in the textfield?

**Kor** · 09-05-2011 03:56 AM

Originally Posted by jagh

How to disallow characters ñÑ in the textfield?

As it is described above.

**jagh** · 09-07-2011 01:32 AM

Thanks, it works. But the space is not allowed to input. I need space to input two names in textbox/textarea (e.g. Maria Ana). How can i define it to this code:

!(/^[A-zÑñ0-9]*$/i).test(f.value)?f.value = f.value.replace(/[^A-zÑñ0-9]/ig,''):null;

**Kor** · 09-07-2011 04:32 AM

Code:

!(/^[A-z&#209;&#241;0-9-\s]*$/i).test(f.value)?f.value = f.value.replace(/[^A-z&#209;&#241;0-9-\s]/ig,''):null;

Read more about regular expressions in javaScript:
http://lawrence.ecorp.net/inet/samples/regexp-intro.php

**DexTeR1911** · 02-10-2013 06:33 AM

Hello!

function valid(f) {
f.value = f.value.replace(/[^A-zÑñ0-9-\s]/ig,'')
}

Works perfect! But, how can i change this to can write . : ! , characters?
Can anyone help me?

**Lukeisme** · 03-22-2013 02:03 PM

[A-zÑ.ñ0-9-\s\.\:\!]

This worked for me.

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