<form action="/search.php">
<div class="input-group my-4">
<input type="text" name="query" class="form-control" placeholder="請輸入關鍵字">
<div class="input-group-append">
<input type="hidden" name="action" value="results">
<button type="submit" class="btn btn-primary"><i class="fa fa-search"
aria-hidden="true"></i></button>
</div>
</div>
</form>