CODEWITHSUNDEEP
javascriptdomoverriding
NoWhereToBeSeen
NoWhereToBeSeen

Reputation: 1444

how do I override appendChild()?

appendChild = function(message) {
    console.log("intercepted!");
}

using the code above does not seem to work.

Anyone knows?

Upvotes: 10

Views: 6697

Answers (2)

lswartsenburg
lswartsenburg

Reputation: 383

It is ill advised to overwrite native functions, but if you do it than make sure you return the appended element as well to prevent problems with code that uses the returned value of the native "appendChild" function: 

window.callbackFunc = function(elem, args) {
  // write some logic here
}
window.f = Element.prototype.appendChild;
Element.prototype.appendChild = function() {
    window.callbackFunc.call(this, arguments);
    return window.f.apply(this, arguments);
};

Upvotes: 4

Denys Séguret
Denys Séguret

Reputation: 382444

What you might want to replace is Element.prototype.appendChild but it's probably a bad idea.

This example adds the text intercepted in the inserted element :

var f = Element.prototype.appendChild;
Element.prototype.appendChild = function(){f.apply(this, arguments);arguments[0].innerHTML="!Intercepted!"; };
document.body.appendChild(document.createElement("div"));

Demonstration

Upvotes: 16

Related Questions