You can use MutationObserver
with characterData
option set to true
<script>
function change() {
document.getElementById("timer").innerHTML = "00:01";
}
function hello() {
alert("Hello");
}
window.onload = function() {
var target = document.querySelector("p");
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(mutation) {
hello()
});
});
var config = {
childList: true,
subtree: true,
characterData: true
};
observer.observe(target, config);
}
</script>
<p id="timer">00:00</p>
<button onclick="change()">My Button</button>