var input = document.getElementById("input");
var result = document.getElementById("result");

function decode() {
	var str = input.value;
	str = str.replace(/\+/g,  " ")
    //result.innerHTML = decodeURIComponent(str).entityify();
    result.innerHTML = unescape(str).entityify();
}

function encode() {
    result.innerHTML = encodeURIComponent(input.value);
}

function isEncoded(str) {
    return (str.indexOf('%') != -1);
}

function inputKeyPress(event) {
    var e = event || window.event;
    
    if ((e.keyCode || e.which) == 13) {
        if (isEncoded(input.value)) {
            decode();
        } else {
            encode();
        }
    }
}

String.prototype.entityify = function () {
    return this.replace(/&/g, "&amp;").replace(/</g,
        "&lt;").replace(/>/g, "&gt;");
};