add option 'require' for textarea form elements

doc/smarty3-templates.md

@@ -177,6 +177,7 @@ Field parameter:
 1. Label for the input box,
 2. Current text for the box,
 3. Help text for the input box.
+4. if set to "required" modern browser will check that this input box is filled when submitting the form,
 
 ### field_yesno.tpl
 

view/templates/field_textarea.tpl

@@ -1,7 +1,7 @@
 
 	<div class="field textarea">
 		<label for="id_{{$field.0}}">{{$field.1}}</label>
-		<textarea name="{{$field.0}}" id="id_{{$field.0}}" aria-describedby="{{$field.0}}_tip">{{$field.2}}</textarea>
+		<textarea name="{{$field.0}}" id="id_{{$field.0}}" aria-describedby="{{$field.0}}_tip"{{if $field.4 eq 'required'}} required{{/if}}>{{$field.2}}</textarea>
 	{{if $field.3}}
 		<span class="field_help" role="tooltip" id="{{$field.0}}_tip">{{$field.3 nofilter}}</span>
 	{{/if}}