Javascript innerHTML is not getting updated

Answer 1

See the comments inline:

// Run when document is completely rendered and is ready to be manipulated 
document.addEventListener("DOMContentLoaded", function () {
    document.querySelector("#global-alert-queue .animate-in").innerHTML = "Change Text";
});

Demo: http://jsfiddle.net/tusharj/kg3cc4gw/3/

querySelector

Returns the first element within the document (using depth-first pre-order traversal of the document's nodes) that matches the specified group of selectors.

More on querySelector: https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelector