I'm developing some guidelines and I can't work out what to call the type of data validation that takes place as the user enters data. i.e. an error message appears as soon as the field is unfocused.

  • In-line data validation?
  • In-situ data validation?
  • Real-time data validation?

Is there a conventional way of referring to this?


The A List Apart article Inline Validation in Web Forms is one of the better posts on this topic and uses a couple of terms to describe this.

They called it "After" validation, which occurs "on blur".

In this version of the form, we displayed a validation message (success or error), after the user indicated that she was done answering a question by moving on to the next one. (This is validating “on blur” in technical speak.)

If you're talking to technical people it's probably just best to call it "On Blur" validation and clarify what that means, a la:

This instance uses On Blur validation (the field is validated after focus leaves the field)

I would only call it "real time" when the field is validated constantly, when the user is still in the field, or "While" as the A List Apart post calls it:

In this variation, we displayed (and updated) a validation message while the user answered each question. (That is, “on key press.”)


On technical note - to circumvent the issue of the user being annoyed by validation happening while they are still working, establish user intent via a timer. Example in jQuery:

jQuery( element ).keyup( function( event ) {

 /* User just entered something, start timer over if it exists */
 clearTimeout( itent_delay );

 /* Schedule your validation function to be initiated in 1.6 seconds */
 itent_delay = setTimeout( function () {
  validate_field( element );
 }, 1600 );


Depending on the type of information being entered, you may want to use a different intent interval. For instance, for a password field, you could make it instant so the user is immediately notified regardless the validity/strength of their password.

On the other hand, for an e-mail field, using a 1.5-2 second intent interval is appropriate, in my opinion.

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