將HTML轉義爲實體，將實體轉回爲HTML

// 將HTML轉義爲實體
function escape(html){
    var elem = document.createElement('div')
    var txt = document.createTextNode(html)
    elem.appendChild(txt)
    return elem.innerHTML;
}
// 將實體轉回爲HTML
function unescape(str) {
    var elem = document.createElement('div')
    elem.innerHTML = str
    return elem.innerText || elem.textContent