How do I strip out all the invalid characters from a textarea input?
I want to allow ASCII characters 32 - 122 except for a few exceptions, such as the apostrophe and the quote.
This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.
Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.
If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.
Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.
Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.
Access the answers to your technology questions today.
30-day free trial. Register in 60 seconds.
Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.
Try it out and discover for yourself.
30-day free trial. Register in 60 seconds.
Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.
You would do that like this:
#rereplace(Form.YourFormfi
This code will output ascii characters 1-127 and show you which ones will be replaced by this regularexpression:
<cfoutput>
<cfloop from="1" to="127" index="i">
#i# #rereplace(chr(i),"(""|'|\
</cfoutput>
As mentioned, whether you wish to use the punctuation class "depends on which punctuation characters you accept." The "punc" class may include characters that are valid punctuation characters, but you do want to exclude them anyway.
>_agx_'s expression will not remove the following characters:
>ASCII / character
> 34 "
>39 '
The Asker said they want to _keep_ quotes. Did you try both examples?
> removes all characters that are not in this list:
> ABCDEFGHIJKLMNOPQRSTUVWXYZ
That can be written as this
<cfoutput>#reReplaceNoCase
You may want to review your requirements against the posted code examples.
1) The "alnum" (alphanumeric) class includes alpha characters outside the range of 32 - 122 like "Ç" or "ä". Do you want to allow these characters or not?
My second example excludes extended alpha characters outside the range of 32 - 122
<cfset newText = reReplace(Form.YourFormfie
SBennet's code does not
<cfset newText2 = rereplace(Form.YourFormfie
2) What about other whitespace characters such as a tab or newline? Do you need
to retain these to preserve text entered in paragraph format? Both my code and SBennet's variation
will exclude newlines
My first example excludes whitespace except for blank spaces AND tab characters
<cfset newText = reReplace(yourText, "([^[:alnum:]|[:blank:]|[:
SBennet's code excludes whitespace except for blank spaces
#rereplace(Form.YourFormfi
Something to think about
>The Asker said they want to _keep_ quotes. Did you try both examples?
Quote from question: "I want to allow ASCII characters 32 - 122 except for a few exceptions, such as the apostrophe and the quote."
this seems to read to me that he wants to allow ASCII characters 32-122 except quotes and apostrophes.
I thought mine met the requirements of the original question exept that I only tested against the common ascii characters (1-127) it is true that alnum and punct will alow other ascii characters so you could use somethinng more like this instead:
<cfoutput>
<cfloop from="1" to="350" index="i">
#i# #rereplace(chr(i),"(""|'|[
</cfoutput>
for your second questions requirement _agx_'s reReplaceNoCase suggestion will work but I would add a space to the allowed characters so the words in the form field stay separated.
<cfoutput>#reReplaceNoCase
I've increased the point value of this question due to:
1. The nature of regular expressions is kind of obscure.
2. I appreciated both your responses.
The simple: reReplaceNoCase(FORM.YourF
was what I was looking for, but others will benefit from this discussion if they find it through doing a Google Search.
> Quote from question: "I want to allow ASCII characters 32 - 122 except for a few exceptions,
>such as the apostrophe and the quote."
Yes. I misread that.
SBennett's last example does seem to meet the original requirements. The code is equivalent to my second example below except that my example does _not_ remove single and double quotes:
#reReplace(yourText, "[^#chr(32)#-#chr(122)#""'
SBennett's last example does
#rereplace(chr(i),"(""|'|[
>>The nature of regular expressions is kind of obscure.
Yeah, It's a shame more programmers don't really know how to use regular expressions, ever since I discovered them about 4-5 years ago, they have been in pretty much every application I have written to some degree. My last boss always laughed at me when I got excited about how easy something would be able to do because I could just write a regular expression. He had never even heard of them until I started working with him.
Business Accounts
Answer for Membership
by: _agx_Posted on 2007-08-21 at 10:51:41ID: 19739939
One option would be to use the character classes. But it depends on which punctuation characters you accept. You can view a description of the classes here. Its an old link but the description seems better than the more recent MX7 documentation.
http://livedocs.adobe.com/
<cfset yourText = "#chr(28)#here"& '"there" and'& "~ everywhere #chr(30)# {else, 'blah', 'blah', blah! }">
<cfset newText = reReplace(yourText, "([^[:alnum:]|[:blank:]|[:
<cfoutput>
yourText: #yourText#<br>
newText: #newText#
</cfoutput>
Another option might be something like this (NOT TESTED)
<cfset yourText = "#chr(28)#here"& '"there" and'& "~ everywhere #chr(30)# {else, 'blah', 'blah', blah! }">
<cfset newText = reReplace(yourText, "[^#chr(32)#-#chr(122)#]",
<cfoutput>
yourText: #yourText#<br>
newText: #newText#
</cfoutput>