_extend.js

// From Underscore.js 1.8.3 (http://underscorejs.org
// (c) 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
// Underscore may be freely distributed under the MIT license.
function _extend(obj)
{
    var length = arguments.length;
    if (length < 2 || obj == null)
    {
        return obj;
    }
    
    for (var index = 1; index < length; index++)
    {
        var source = arguments[index],
            keys = [];
        for (var key in obj)
        {
            keys.push(key);
        }
        var l = keys.length;
        
        for (var i = 0; i < l; i++)
        {
            var key = keys[i];
            obj[key] = source[key];
        }
    }
    
    return obj;
}