Form validation

[DM]

I'm a newbie in javascript, and came across this problem:

I have a form with several fields, and I need to validate the form. For each
field that needs validation, I include the following:

-------------------------------------
<tr><td >Email:</td><td><input type="text" name="email" value="$email"
onChange="retur n ValidateEmail(t his);"/></td></tr>
-------------------------------------
function ValidateEmail(e ntered)
{

var re_email=/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,} )+$/

if(re_email.tes t(entered.value ))
{
}
else {
alert("Invalid email.")
}
}
-----------------------------

It works fine... except: if I enter an invalid email it prompts me with an
error message, and continue (without changing the email address), the
validation is not done again. I tried onBlur instead of onChange, but I get
the same results.

Can anyone suggest how to avoid this problem? Thanks.

[Julia deSilva]

Re: Form validation

> -------------------------------------[color=blue]
> function ValidateEmail(e ntered)
> {
>
> var re_email=/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,} )+$/
>
> if(re_email.tes t(entered.value ))
> {
> }
> else {
> alert("Invalid email.")
> }
> }
> -----------------------------
>
> It works fine... except: if I enter an invalid email it prompts me with[/color]
an[color=blue]
> error message, and continue (without changing the email address), the
> validation is not done again. I tried onBlur instead of onChange, but I[/color]
get[color=blue]
> the same results.[/color]

You have to return a boolean value from the function (true | false)
depending on whether
your email string fits the pattern. You'd also want to set the focus back to
the form element with the problem.

This should give you a structure to start things off.

function ValidateEmail(f ormelement) {
if (email_is_bad) {
return false;
formelement.foc us();
}
else true;
}

[Dr John Stockton]

Re: Form validation

JRS: In article <Rglpb.1247$mB5 .217532@news20. bellglobal.com> , seen in
news:comp.lang. javascript, DM <dm@nospam.co m> posted at Sun, 2 Nov 2003
23:59:28 :-[color=blue]
>
>var re_email=/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,} )+$/
>
>if(re_email.te st(entered.valu e))[/color]

That rejects j+a@b.cc which I believe to be a permissible address;
likewise j$a@b.cc

When validating, it is rather important that everything legitimate
should be accepted.

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 MIME. ©
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