Fastest method to escape HTML tags as HTML entities?

Question

I\'m writing a Chrome extension that involves doing a lot of the following job: sanitizing strings that might contain HTML tags, by converting

Answer 1

All-in-one script:

// HTML entities Encode/Decode

function htmlspecialchars(str) {
    var map = {
        "&": "&",
        "<": "<",
        ">": ">",
        "\"": """,
        "'": "'" // ' -> ' for XML only
    };
    return str.replace(/[&<>"']/g, function(m) { return map[m]; });
}
function htmlspecialchars_decode(str) {
    var map = {
        "&": "&",
        "<": "<",
        ">": ">",
        """: "\"",
        "'": "'"
    };
    return str.replace(/(&|<|>|"|')/g, function(m) { return map[m]; });
}
function htmlentities(str) {
    var textarea = document.createElement("textarea");
    textarea.innerHTML = str;
    return textarea.innerHTML;
}
function htmlentities_decode(str) {
    var textarea = document.createElement("textarea");
    textarea.innerHTML = str;
    return textarea.value;
}

http://pastebin.com/JGCVs0Ts