// Core javascript helper functions

// Cross-browser event handlers.
function addEvent(obj, evType, fn) {
    if (obj.addEventListener) {
        obj.addEventListener(evType, fn, false);
        return true;
    } else if (obj.attachEvent) {
        var r = obj.attachEvent("on" + evType, fn);
        return r;
    } else {
        return false;
    }
}

function removeEvent(obj, evType, fn) {
    if (obj.removeEventListener) {
        obj.removeEventListener(evType, fn, false);
        return true;
    } else if (obj.detachEvent) {
        obj.detachEvent("on" + evType, fn);
    } else {
        return false;
    }
}

// quickElement(tagType, parentReference, textInChildNode, [, attribute, attributeValue ...]);
function quickElement() {
    var obj = document.createElement(arguments[0]);
    if (arguments[2] != '' && arguments[2] != null) {
        var textNode = document.createTextNode(arguments[2]);
        obj.appendChild(textNode);
    }
    var len = arguments.length;
    for (var i = 3; i < len; i += 2) {
        obj.setAttribute(arguments[i], arguments[i+1]);
    }
    arguments[1].appendChild(obj);
    return obj;
}





//-----------------------------------------------------------------------------
// Date object extensions
// ----------------------------------------------------------------------------
Date.prototype.getCorrectYear = function() {
    // Date.getYear() is unreliable --
    // see http://www.quirksmode.org/js/introdate.html#year
    var y = this.getYear() % 100;
    return (y < 38) ? y + 2000 : y + 1900;
}

Date.prototype.getTwoDigitMonth = function() {
    return (this.getMonth() < 9) ? '0' + (this.getMonth()+1) : (this.getMonth()+1);
}

Date.prototype.getTwoDigitDate = function() {
    return (this.getDate() < 10) ? '0' + this.getDate() : this.getDate();
}

Date.prototype.getTwoDigitHour = function() {
    return (this.getHours() < 10) ? '0' + this.getHours() : this.getHours();
}

Date.prototype.getTwoDigitMinute = function() {
    return (this.getMinutes() < 10) ? '0' + this.getMinutes() : this.getMinutes();
}

Date.prototype.getISODate = function() {
    return this.getCorrectYear() + '-' + this.getTwoDigitMonth() + '-' + this.getTwoDigitDate();
}

Date.prototype.getHourMinute = function() {
    return this.getTwoDigitHour() + ':' + this.getTwoDigitMinute();
}

// ----------------------------------------------------------------------------
// String object extensions
// ----------------------------------------------------------------------------
String.prototype.pad_left = function(pad_length, pad_string) {
    new_string = this;
    for (var i = 0; new_string.length < pad_length; i++) {
        new_string = pad_string + new_string;
    }
    return new_string;
}