What does this.optional(element) do when adding a jQuery validation method?
Solution 1
OK... so in your examples, the field is never blank in either form. Either it has a placeholder value, or an attempt at an email address. The whole point of this.optional(element)
is to immediately return true if the element is blank AND it is not required.
So if you had these two methods:
jQuery.validator.addMethod("BOB", function (value, element) {
return this.optional(element) ||
element.value === 'BOB';
}, 'You did not enter BOB');
jQuery.validator.addMethod("mustbeBOB", function (value, element) {
return element.value === 'BOB';
}, 'You did not enter BOB');
Adding a class of BOB required
would be the same as entering a class of mustbeBOB
. Compare that to having a class of BOB
which would allow for a blank or "BOB", vs a class of mustbeBOB
which will only pass validation with a value of BOB
, blank would fail. Does that make more sense?
Solution 2
this.optional
is intended to be used in general-purpose validation methods, which might be used with required or optional elements. It allows them to skip all their own checks if the field is not filled in. If the field is optional and blank, the method calling this.optional
returns successfully immediately.
By using this, the method can assume that the value is non-empty, which can simplify the rest of its coding.
Comments
-
Mori almost 2 years
Please see the documentation:
https://jqueryvalidation.org/jQuery.validator.addMethod/I wonder what
this.optional(element)
does. I created two forms to test:
Form1 and Form2 — one withthis.optional(element)
and the other without it. Theoretically speaking and according to a couple of comments on this answer by Andrew Whitaker:all
this.optional
does is say "if the field is optional, return true if it is blank"and
The
this.optional
check is basically checking to see if the field is blank or not before evaluating whether or not it meets the rule.But in action I see no difference in how Form1 and Form2 work. Please help me understand the difference in action.
-
Mori over 11 yearsHelpful example! That means using
this.optional(element)
is meaningless if the field is required or has a default value, right?