Attachment mandatory & non mandatory based on variable condition

[ShrutikaD]

Hi 

I want to make attachment mandatory based on condition which is working fine.(on portal)

here is the code

var mode = g_form.getValue('mode');

   if((mode == 'eft')&&(this.document.getElementsByClassName('get-attachment').length == 0))  {

                g_form.addErrorMessage('Please attach required file/s');

                return false;

}

I need to add one more combination to this condition when mode==eft && id ==yes  then attachment should NOT be mandatory.

please suggest how to achieve this