Validate field value by javascript before submitting an item

I want to validate field value of item before submitting using javascript. I know there is a function onBeforeSaveField to achieve this, I think that this function works on server side. I want to validate it on client side using javascript.

Yes onBeforeSaveField is server side.

I think it is best to make a Faq article for this

Thanks for your reply.
Actually I have some dynamic fields, one of these field should have some value. I want to validate it before submitting item.
As you suggest to read FAQ, that was not my requirement.
I can validate only one field on 'BLUR' event.

Hello

there is a misunderstanding
- i have not asked you to read the FAQ artcile

i said that i want to write a new article
i have not written it yet
(it does not exist yet !)

please answer this question:
is the field that you want to custom validate is a "text/number/custom validation" field ??

(then if it is of the above type, you can add your custom validation via a parameter)

Field types are text and select.

How can I validate it via parameter..??

Hello

yes in text field you can enable "custom" validation

and then configure the custom validation via parameter
also an input "mask" will be shon to the user

How to validate select field...??

hhmm

but select field has preset values
- so it already shows the values that are valid

Sorry, I did not get you.

How can I validate some fields on clicking save button of item....??

Hello

all fields have validation when form save is clicked
validation is happening according to parameters

1. most basic validation is "required"

2. chekckbox , chekckbox image, selectmultiple also have
- minumum and maximum number of values

3. multi-property field like address international can also have some properties e.g. "city", "country" as required

4. some field have specific validation e.g. e-mail field, has email format validation, weblink field has URL validation

5. then the free input field "text",
- you can select from a set of a preset validation, e.g "float" e.g. "integer" e.g. "url"
- you can also configure a full custom format + masking (see parameter)

About the select field, it has a preconfigured drop down of values, it does not have free selection !


(Finally irrelevant to your question but i will mention it) even if users hacks the form to submit a different value, the server side validation will reject it
e.g. allowed values 1, 2, 3
and form submits 4 , value will not be saved