Object.defineProperty(
Element.prototype,
"insertAfter", {
enumerable: false,
value: function(nodeBefore){
if(nodeBefore.parentNode){
nodeBefore.parentNode.insertBefore(this, nodeBefore.nextSibling);
}
else{
throw new TypeError("Element is not in DOM.");
}
}
}
);
//Benutzung:
var div = document.createElement("div");
div.textContent = "inserted after";
div.insertAfter(document.getElementById("elementBefore"));