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javascript email, ip or dns validation

Posted on 2012-08-24
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Last Modified: 2012-08-27
hi, i have the following piece of code to validate an address - either an email, or a dns or even an ip address - allowing % for wildcards.
the regular expression script is below:
var ml = /^([0-9a-z]([-.\w]*[0-9a-z])*@(([0-9a-z])+([-\w]*[0-9a-z])*\.)+[a-z]{2,6})$/i;
var ip = /^[\d%]{1,3}\.[\d%]{1,3}\.[\d%]{1,3}\.[\d%]{1,3}$/i;
var dn = /^(?![0-9]+$)(?!-)[a-zA-Z0-9%-]{,63}(?<!-)$/i;
if (!ml.test(eml) || !ip.test(eml) || !dn.test(eml)) {
	salert("Invalid E-Mail, IP or DNS Address detected!\n\nMust either be a valid E-Mail,\nor a valid IP or DNS address - allowing for % subdomain wildcards.");
	document.getElementById("ajaxbg").style.visibility = "hidden";
	document.form_blacklist.text_listedaddress.focus();
	return false;
}

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however, on ,line 3 where var dn is defined it shows an error in my editor (adobe dreamweaver) - and unfortunately i am blind to see what exactly the issue is...
could somebody please help?
the references used were http://stackoverflow.com/questions/2063213/regular-expression-for-validating-dns-label-host-name and the ip i just added a basic validation check. the purpose of this is to block certain ip addresses, email addresses and host names from submitting a form (they have been known to spam our system).
oh - google chrome's developer tools, the console reports the following: Uncaught SyntaxError: Invalid regular expression: /^(?![0-9]+$)(?!-)[a-zA-Z0-9%-]{,63}(?<!-)$/: Invalid group but - i do not see how or where as i think that there are multiple groups here - which one is the issue?
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Question by:intellisource
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5 Comments
 
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Accepted Solution

by:
zappafan2k2 earned 2000 total points
ID: 38329471
It's the < character in the last group
try this:
var dn = /^(?![0-9]+$)(?!-)[a-zA-Z0-9%-]{,63}(?!-)$/i;
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LVL 10

Expert Comment

by:tdlewis
ID: 38330386
In addition to the < character, you have two other problems:
1. There is no lower bound for the length of the domain name.
2. Everything you test must simultaneously be a valid email, IP, and DNS.

Try this:
var dn = /^(?![0-9]+$)(?!-)[a-zA-Z0-9%-]{1,63}(?!-)$/i;
if (!ml.test(eml) && !ip.test(eml) && !dn.test(eml)) {

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Author Comment

by:intellisource
ID: 38331996
unfortunately tdlewis, it is either or not and - it's for a blacklist database. its to block form submission requests - either by email, ip or dns. the first option was correct thanks :)
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Author Closing Comment

by:intellisource
ID: 38332037
thanks zappafan2k2... wonder why he had that character there? it's not valid in host names...
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Author Comment

by:intellisource
ID: 38336059
my apologies tdlewis, you were correct regarding the validation if statement... a bit of reverse logic there lol
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