Brian2011

This code will validate an email address to ensure the user enters an email address in the correct format:

<script Language="Javascript">
<!--
function checkform(theform){

var EmailOk = true
var Temp = theform.email
var AtSym = Temp.value.indexOf('@')
var Period = Temp.value.lastIndexOf('.')
var Space = Temp.value.indexOf(' ')
var Length = Temp.value.length - 1
if ((AtSym < 1) ||
(Period <= AtSym+1) ||
(Period == Length ) ||
(Space != -1)){
EmailOk = false
alert('Please enter a valid e-mail address!')
theform.email.focus();
return (false);}

}
//-->
</script>

Example form code:

<form method=" POST" action="/success.htm" onsubmit="return checkform(this)" name="myform">


When this form is submitted, the javascript runs and will only go to '/success.htm' if user enters a correctly formatted email address.
????: NamePros.com http://www.namepros.com/programming/740733-email-form-validation-javascript.html

If the user does not enter a correctly formatted email address, a pop up alert box appears to let them know.

nasaboy007

Keep in mind that client-side validation is just for the sake of user experience and in no way should be depended on. Everything should be revalidated on the server side as well.

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Mark Talks

A nice little script and I can think of several uses where it would be handy in full or in part, such as free forum/site software that don't allow for open source editing and/or PHP support.

But, with users being able to disable JS and/or manipulate it easier, it's definitely got it's risk. Nice little script though

4pm

sorry to say but this script checks very few things.. for example it will let thru the following bogus emails as valid ones:

a@b@c._
....@...x
.xyz
*&^%$#@@@@(.)>>


and so on..

you'll also screw the users that input empty space before or after (happen often when copy-pasting) valid email and will be presented with error message..

i would google "javascript email validation" for good ready to use reliable regex example (there are many to choose from) - correct email validation in javacript (as well as in php) could not be implemented effectively without regex imo

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Brian2011

Yeah, the script does have some drawbacks as you mention but it is a good starting point and weeds out most email address input errors. Of course it doesn't work for those who are determined to enter a wrong email address.

I agree that regex would be able to check input to a finer degree but understanding how regex works can be a little daunting for some.

Here's another little bit of code for ASP programmers that will convert text to proper case as there is no built-in function in VBScript to do this:

<%
''''''' FUNCTION TO CAPITALIZE THE FIRST CHARACTER OF EACH WORD IN THE INPUT STRING '''''''''
Function PCase(strInput)
iPosition = 1
Do While InStr(iPosition, strInput, " ", 1) <> 0
iSpace = InStr(iPosition, strInput, " ", 1)
strOutput = strOutput & UCase(Mid(strInput, iPosition, 1))
strOutput = strOutput & LCase(Mid(strInput, iPosition + 1, iSpace - iPosition))
iPosition = iSpace + 1
Loop
strOutput = strOutput & UCase(Mid(strInput, iPosition, 1))
StrOutput = strOutput & LCase(Mid(strInput, iPosition + 1))
PCase = strOutput
????: NamePros.com http://www.namepros.com/showthread.php?t=740733
End Function
'''''''''''''''''''''''''''''''' END FUNCTION '''''''''''''''''''''''''''''''''''''''''''''''
%>

...so 'peter Smith' or 'PeTER smiTH' becomes 'Peter Smith'

<%
' example
Str = "PeTER smiTH"
Str = PCase(Str)
Response.write(Str)
%>


Hope this is useful to someone :-)

4pm

basic user-side errors in emails can be handled more accurately in this way:

the function returns false if the string does not look like email address and true otherwise.
yet the strings like ...@...abcd still get thru so if you need more robust solution check http://www.regular-expressions.info/email.html for fast examples

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