<form?action="/contest/vacation-photo/{year}/{month}"?class="form-horizontal"?role="form"?enctype="multipart/form-data"?method="POST"> ????<div?class="form-group"> ????????<label?for="fieldName"?class="col-sm-2?control-label">Name</label> ????????<div?class="col-sm-4"> ????????????<input?type="text"?class="form-control"?id="fieldName"?name="name"> ????????</div> ????</div> ????<div?class="form-group"> ????????<label?for="fieldEmail"?class="col-sm-2?control-label">Email</label> ????????<div?class="col-sm-4"> ????????????<input?type="text"?class="form-control"?id="fieldEmail"?name="email"?required> ????????</div> ????</div> ????<div?class="form-group"> ????????<label?for="fieldPhoto"?class="col-sm-2?control-label">Vacation?photo</label> ????????<div?class="col-sm-4"> ??????????? ????????</div> ????</div> ????<div?class="form-group"> ????????<div?class="col-sm-offset-2?col-sm-4"> ????????????<button?type="submit"?class="btn?btn-primary">Submit</button> ????????</div> ????</div> </form>上述代碼中的第一行form中的：action="/contest/vacation-photo/{year}/{month}"這里是handlebars的模板引擎，照理說應(yīng)該用{{}}，怎么這里用了{}？？？？？