I have made a chrome extension for this purpose, named Js-Injector. It is available from github on https://github.com/shahverdy/JS-Injector. Unfortunately I can not deploy it on Chrome Web Store, because of US sanctions on my country. There are some samples in extension for this purpose, you can easily work with it.

In Js-Injector you can add the following code for your website:

$(function(){
    $("a[href='ad.com']").remove();
})