Tutorial 7: Javascript: So you want to know attr ids in your page or no. of duplicate ids

open console (F12)
It will require jquery.
paste

var ids = []; $('div[id]').each(function(){ ids.push( this.id ); });

it contains all the ids in your page.

To find unique ids just perform following function on result from previous step
$.unique(ids) 


So now you know how many duplicate ids you have left in your page