Setting error message in html with knockout validation -

i use knockout-validation adding validation rules in html5, works great:

http://jsfiddle.net/gt228dgm/1/

i change default error messages generated browser (like "this field required." or "invalid"). pretty done in javascript code, believe kind of texts should go html. possible , how? guess i'm looking like:

<input data-bind='value: firstname, validate: { message: "please enter first name" }' required pattern="^[a-za-z]{1,255}$"/></label> 

i have implemented custom knockout binding solves issue:

ko.bindinghandlers.validate = {     init: function(element, valueaccessor, allbindings, viewmodel, bindingcontext) {          var valuebinding = allbindings().value;         var value = valueaccessor();          if (value) {             valuebinding.extend(value);         }     } }; 

the binding looks this

<input data-bind='value: firstname, validate: { required: { message: 'full name missing' }, pattern: { message: 'full name should max. 255 alphanumeric characters' } }' required pattern="^[a-za-z]{1,255}$"/> 

any other suggestions?