Answers for "add a custom attribute to an element in jquery"

jquery add attribute

$('#someid').attr('name', 'value');

custom attribute jquery selector

$("ul[data-group='Companies'] li[data-company='Microsoft']") //Get all elements with data-company="Microsoft" below "Companies"

$("ul[data-group='Companies'] li:not([data-company='Microsoft'])") //get all elements with data-company!="Microsoft" below "Companies"