Check if a input box is empty

Question

How can I check if a given input control is empty? I know there is $pristine property on the field which tells that if a given field is empty initially but what

Answer 1

If your textbox is a Required field and have some regex pattern to match and has minlength and maxlength

TestBox code

Ng-Class to Add

ng-class="{ 'err' :  myform.myfieldname.$invalid || (myform.myfieldname.$touched && !model.myfieldmodel.length) }"