Implement the outerHTML property for browsers that don't support it

outerHTML.js

// Implement the outerHTML property for browsers that don't support it.
// Assumes that the browser does support innerHTML, has an extensible 
// Element.prototype, and allows getters and setters to be defined.
(function() {
 // If we already have outerHTML return without doing anything
 if (document.createElement("div").outerHTML) return;
 
 // Return the outer HTML of the element referred to by this
 function outerHTMLGetter() {
 var container = document.createElement("div"); // Dummy element
 container.appendChild(this.cloneNode(true)); // Copy this to dummy
 return container.innerHTML; // Return dummy content
 }
 
 // Set the outer HTML of the this element to the specified value
 function outerHTMLSetter(value) {
 // Create a dummy element and set its content to the specified value
 var container = document.createElement("div");
 container.innerHTML = value;
 // Move each of the nodes from the dummy into the document
 while(container.firstChild) // Loop until container has no more kids
 this.parentNode.insertBefore(container.firstChild, this);
 // And remove the node that has been replaced
 this.parentNode.removeChild(this);
 }
 // Now use these two functions as getters and setters for the 
 // outerHTML property of all Element objects. Use ES5 Object.defineProperty
 // if it exists and otherwise fall back on __defineGetter__ and Setter__.
 if (Object.defineProperty) {
 Object.defineProperty(Element.prototype, "outerHTML", {
 get: outerHTMLGetter,
 set: outerHTMLSetter,
 enumerable: false, configurable: true
 });
 }
 else {
 Element.prototype.__defineGetter__("outerHTML", outerHTMLGetter);
 Element.prototype.__defineSetter__("outerHTML", outerHTMLSetter);
 }
}());