update data-placeholder example

demos/demos/webforms.html

@@ -193,7 +193,7 @@ <h3>Simple Demo</h3>
 						<label for="date">
 							date: *
 						</label>
-						<input name="date" placeholder="year-month-day" type="date" id="date" required form="form" />
+						<input name="date" data-placeholder="year-month-day" type="date" id="date" required form="form" />
 					</div>
 
 					<div class="form-item">