How to run a selector on a dynamically generated page?

Question

I have a selector which works in GM_addStyle but not in jQuery. I want to use jQuery :contains() which is not available in CSS3.

But, it appear

Answer 1

Waiting for the element:

function waitForElement(id, callback, timeout){
    if('undefined' == typeof timeout) timeout = 30;
    timeout = timeout * 1000;
    var time = 0;
    var poops = setInterval(function(){
        if(time >= timeout) clearInterval(poops);
        if(document.getElementById(id)){
            clearInterval(poops);
            callback();
        }
        time += 100;
    }, 100);
}

One way to include jQuery:

(function(callback) {
  var script = document.createElement("script");
  script.setAttribute("src", "//code.jquery.com/jquery-1.11.3.min.js");
  script.addEventListener('load', callback);
  document.body.appendChild(script);
})

// main codez go in here
(function(){
  window.alert($('a').length+" Links");
});