abalytics.js

// Open Source Initiative OSI - The MIT License (MIT):Licensing
//
// The MIT License (MIT)
// Copyright (c) 2012 Daniele Mazzini - https://github.com/danmaz74
//
// Version: 1.1
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy,
// modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
// OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

var ABalytics = {
    changes: [],
    // for each experiment, load a variant if already saved for this session, or pick a random one
    init: function(config, __gaq, start_slot) {
        if (typeof(start_slot) == 'undefined') start_slot = 1;

        for (var experiment in config) {
            var variants = config[experiment];

            // read the saved variant for this experiment in this session, or pick a random one and save it
            var variant_id = this.readCookie("ABalytics_"+experiment);
            if (!variant_id || !variants[variant_id]) {
                // pick a random variant
                variant_id = Math.floor(Math.random()*variants.length);
                document.cookie = "ABalytics_"+experiment+"="+variant_id+"; path=/";
            }

            var variant = variants[variant_id];

            // ga.js changes _gaq into an object with a custom push() method but no concat,
            // so we have to push each _setCustomVar individually
            __gaq.push(['_setCustomVar',
                start_slot,
                experiment,                 // The name of the custom variable = name of the experiment
                variant.name,               // The value of the custom variable = variant shown
                2                           // Sets the scope to session-level
            ]);
            start_slot++;

            for (var change in variant) {
                if (change != 'name') this.changes.push([change,variant[change]]);
            }
        }
    },
    // apply the selected variants for each experiment
    applyHtml: function() {
        for (var i=0;i<this.changes.length;i++) {
            var change = this.changes[i];
            var elements = document.getElementsByClassName ? document.getElementsByClassName(change[0]) : this.getElementsByClassName(change[0]);

            for (var j=0;j<elements.length;j++) elements[j].innerHTML = change[1];
        }
    },
    readCookie: function(name) {
        var nameEQ = name + "=";
        var ca = document.cookie.split(';');
        for(var i=0;i < ca.length;i++) {
            var c = ca[i];
            while (c.charAt(0)==' ') c = c.substring(1,c.length);
            if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
        }
        return null;
    },
    getElementsByClassName: function(className)
    {
        var hasClassName = new RegExp("(?:^|\\s)" + className + "(?:$|\\s)");
        var allElements = document.getElementsByTagName("*");
        var results = [];

        var element;
        for (var i = 0; ((element = allElements[i]) != null) && (element != undefined); i++) {
            var elementClass = element.className;
            if (elementClass && elementClass.indexOf(className) != -1 && hasClassName.test(elementClass))
                results.push(element);
        }

        return results;
    }
};