best form validation

[pradeepjain]

Hii guys,
My site has whole lots of forms...i wanted to know which is the best method for form validation.

say using ajax or javascript and server side or any other..if there is any example it would be better

[Dormilich]

If I have to do form validation I usually run a client side validation (JS) so that the user may correct the entries and a server side validation to check if really all fields were filled correctly.

[pradeepjain]

I am also following the same thing as of now..i was thinking of Ajax ...but i got answers that
it uses lots of server resourse ..

[dlite922]

@pradeepjain
You don't need ajax for validation. If you've got a long form, I would assist the user along with JavaScript to get as much of the form right as possible. At that point I would use the bandwidth to validate. If my code is right and it's a legitimate user, I shouldn't get any failed validations server side, those people who are going to hack it, will get my server-side error message.

If you've got a short forum and don't mind the traffic/resource of submitting the form for validation, I would just do it that way. Why do the wort twice.

Second reason to do it on client-side too is for usability. It's so nice to have a phone number formatted and counted to make sure I didn't miss a digit. Some forms put a green check mark next to each field I fill out if its correct and a red X for those that are incorrect after I've left that field.


Dan

[pradeepjain]

yup the thing u told putting x mark and tick mark needs ajax scripting i guess

[dlite922]

@pradeepjain
no not really. Depends on what your validating. If your validating an email address, you can use JavaScript since you already know what an email "should" look like.

But for example you need to check if a username has been taken, you need to query your database, and for this you need Ajax.




Dan

[pradeepjain]

my form does need to validate only few fields like phone,email..etc....i use pop up msg on submit ......can u show me an example for wht u told like x mark and tick mark with javascripts....

[dlite922]

it is basic JavaScript really, there's no trick. All your doing is changing the display value of an image. (See Google for more info) You have two images that are off by default. (Display: none with CSS). With javascript you turn on the one that corresponds to the validation.

simple example:

if(valid)
{
  document.getElementById('emailImageCheck').style.display = "block"; // or inline 
}  
else
{
  document.getElementById('emailImageRedX').style.display = "block"; // or 
}
 

Dan

[pradeepjain]

i guess u were talking of form like this
Javascript form validation - doing it right

i really dont understand without any examples :(

[dlite922]

@pradeepjain
Yes, like that. except instead of red text you would do the lines I typed in my previous post.

You learn coding by trying. Beginning coders copy and paste. Then you change the code. And then you learn to memorize and use references and Google less and less.

This is a path everybody takes. No one learns outright code by memorization.


Dan

[Markus]

You need a combination of both Javascript, although it isn't required, and PHP. If you're going to use one and not the other, then you must use PHP. The reason to this is: Javascript is not always enabled on the browser, and if your validation relies on javascript, in a browser that doesn't have it enabled, your validation is useless.

[pbmods]

Moving to the Javascript forum for now.

[acoder]

pradeepjain,

post your code and explain what you've tried and the parts you're struggling with. In the link, you can just view the source to see the code and adapt it to your requirements.