//To do this simply create a element in the DOM tree and
//set the innerText of the element to your string.
//Then retrieve the innerHTML of the element.
//The browser will return an HTML encoded string.
function HtmlEncode(s)
{
var el = document.createElement("div");
el.innerText = el.textContent = s;
s = el.innerHTML;
return s;
}
console.log(HtmlEncode('&;'><"'));
//expected output: &;'><"