var elemProto = HTMLElement.prototype;

var configurables = [];

var prop;

var desc;

​

for (prop in elemProto) {

  desc = Object.getOwnPropertyDescriptor(elemProto, prop);

  if (desc && desc.configurable) {

    configurables.push(prop);

  }

}

​

console.log(configurables);

console.log('contentEditable' in elemProto);

​

// Chrome 48 >

// ["title", "lang", "translate", "dir", "dataset", "hidden", "tabIndex", "accessKey", "draggable", "spellcheck", "contentEditable", "isContentEditable", "offsetParent", "offsetTop", "offsetLeft", "offsetWidth", "offsetHeight", "style", "innerText", "outerText", "webkitdropzone", "onabort", "onblur", "oncancel", "oncanplay", "oncanplaythrough", "onchange", "onclick", "onclose", "oncontextmenu", "oncuechange", "ondblclick", "ondrag", "ondragend", "ondragenter", "ondragleave", "ondragover", "ondragstart", "ondrop", "ondurationchange", "onemptied", "onended", "onerror", "onfocus", "oninput", "oninvalid", "onkeydown", "onkeypress", "onkeyup", "onload", "onloadeddata", "onloadedmetadata", "onloadstart", "onmousedown", "onmouseenter", "onmouseleave", "onmousemove", "onmouseout", "onmouseover", "onmouseup", "onmousewheel", "onpause", "onplay", "onplaying", "onprogress", "onratechange", "onreset", "onresize", "onscroll", "onseeked", "onseeking", "onselect", "onshow", "onstalled", "onsubmit", "onsuspend", "ontimeupdate", "ontoggle", "onvolumechange", "onwaiting", "click", "focus", "blur", "onautocomplete", "onautocompleteerror"]

​

// Safari 9 >

// ["insertAdjacentElement", "insertAdjacentHTML", "insertAdjacentText", "click"]

​