Configuration

Knockout Validation has several configuration options to help tailor it to your needs.

Option	Default	Description
insertMessages	true	If true validation will insert either a <span> element or the template specified by messageTemplate after any element (e.g. <input>) that uses a KO value binding with a validated field.
decorateInputElement	false	Indicates whether to assign an error class to the <input> tag when your property is invalid. Note that this was previously called decorateElement, and this config option was renamed 2013-11-21.
errorMessageClass	‘validationMessage’	The CSS class assigned to validation error messages inserted when insertMessages is true
errorElementClass	‘validationElement’	The CSS class assigned to validation error <input> elements, must have decorateInputElement set to true
errorsAsTitle	true	Shows tooltips using input ‘title’ attribute. False hides them
errorClass	null	If defined, the CSS class assigned to both <input> and validation message elements
parseInputAttributes	false	Indicates whether to assign validation rules to your ViewModel using HTML5 validation attributes
writeInputAttributes	false	Adds HTML5 input validation attributes to form elements that ko observable’s are bound to
messagesOnModified	true	Indicates whether validation messages are triggered only when properties are modified or at all times
decorateElementOnModified	true	Indicates whether css error classes are added only when properties are modified or at all times
messageTemplate	null	The id of the <script type="text/html"></script> that you want to use for all your validation messages
grouping	{ deep: false, observable: true, live: false }	When using the group or validatedObservable functions: • deep indicates whether to walk the ViewModel (or object) recursively, or only walk first-level properties. • observable indicates whether the returned errors object is a ko.computed or a simple function. • live indicates whether changes to observableArrays inside the model should cause the validator to re-run.
registerExtenders	true	Register custom validation rules defined via ko.validation.rules

If you would like to change the default configurations, you have a couple options for how to do that:

• Use the ko.validation.init( /* options object */ ); function
• Use the ko.applyBindingsWithValidation(viewModel, rootNode, /*options object */ ); function **contextual
• Use the data-bind="validationOptions: /*options object */" binding **contextual

**contextual – this means the validation options that you use only apply to the current node and children. You can define different validation options for different html node contexts on your page!!