toogle fullscreen when click something

toggle-fullscreen.js

// ref: https://davidwalsh.name/fullscreen

// let's bind the event on body element
var e = document.body;

e.onclick = function() {

    if (prefixed(document, "fullScreen") || prefixed(document, "isFullScreen")) {
        prefixed(document, "cancelFullScreen");
    } else {
      
        // note: requestFullScreen method is not on document
        prefixed(e, "requestFullScreen");
    }

}

function prefixed(obj, method) {

    var pfx = ["webkit", "moz", "ms", "o", ""];

    var p = 0, m, t;
    while (p < pfx.length && !obj[m]) {
        m = method;
        if (pfx[p] !== "") {
            m = m.substr(0, 1).toUpperCase() + m.substr(1);
        }
        m = pfx[p] + m;
        t = typeof obj[m];
        if (t != "undefined") {
            pfx = [pfx[p]];
            return (t == "function" ? obj[m]() : obj[m]);
        }
        p++;
    }
}