switch_v_object.js

// Safari reports "0" when no port is in the href
// IE reports "80" when no port is in the href
function getPortUsingSingleTernaryOp (url) {
    var port, a = document.createElement('a');
    a.href = url;
    return (url.indexOf(":" + a.port) > -1) ? a.port : "";
}

function getPortUsingTernaryOp (url) {
    var port, a = document.createElement('a');
    a.href = url;
    return (
        a.port == "" || a.port == "0"? "" :
        a.port == "80" && url.indexOf(":" + a.port) >= 0? "" :
        a.port );
}

function getPortUsingSwitch (url) {
    // Safari reports "0" when no port is in the href
    // IE reports "80" when no port is in the href
    var port, a = document.createElement('a');
    a.href = url;
    
    // using switch
    switch (a.port) {
        case "0":   port = (url.indexOf(":0") > -1) ? "0" : ""; break;
        case "80":  port = (url.indexOf(":80") > -1) ? "80" : ""; break;
        default:    port = a.port;
    }
    return port;
}

function getPortUsingObjectLiteral (url) {
    // Safari reports "0" when no port is in the href
    // IE reports "80" when no port is in the href
    var port, a = document.createElement('a');
    a.href = url;
    
    // using object literal
    var portDefaults = {
        '0': function () { return (url.indexOf(":0") > -1) ? "0" : ""; },
        '80': function () { return (url.indexOf(":80") > -1) ? "80" : ""; } 
    };
    if (typeof portDefaults[a.port] !== 'function') {
        port = a.port;
    } else {
        port = portDefaults[a.port]();
    }
    
    return port;
}