表单元素的html表单元素与php函数

I am using an open source PHP ERP Application. I found something new over there. The application uses different methods for form elements ex : Instead of below

<input id="employee_name" class="textfield employee_name" type="text" data-toggle="tooltip" title="" placeholder="" size="20" maxlength="256" value="Eric Stock" name="employee_name[]">

I see a php function (method actually) like

<?php $f->text_field_d() ?>

The application is quite big and I guess would have 300/400 forms and there are single forms which contains 100 + such input/select/check box element.

So, my question is

1. Is this standard in PHP to use some functions/instead of actual HTML
2. Does it impact the performance ; I plan to do some customization so should I use plain text or use these kind of functions

It's not necessarily standard. It's how much do want to re-write the same code over again. The parameter would just be passed to the php function, and the function will do the rest. It doesn't impact performance.