if (!Array.prototype.push) Array.prototype.push = function() {for (var i=0; i<arguments.length; i++) this[this.length] = arguments[i];return this.length;}

Array.prototype.find = function(value, start) {start = start || 0;for (var i=start; i<this.length; i++)

if (this[i]==value)

return i;return -1;}

Array.prototype.has = function(value) {return this.find(value)!==-1;}

function map(list, func) {var result = [];func = func || function(v) {return v};for (var i=0; i < list.length; i++) result.push(func(list[i], i, list));return result;}

function filter(list, func) {var result = [];func = func || function(v) {return v};map(list, function(v) { if (func(v)) result.push(v) } );return result;}

function getElem(elem) {if (document.getElementById) {if (typeof elem == "string") {elem = document.getElementById(elem);if (elem===null) throw 'cannot get element: element does not exist';} else if (typeof elem != "object") {throw 'cannot get element: invalid datatype';}} else throw 'cannot get element: unsupported DOM';return elem;}

function hasClass(elem, className) {return getElem(elem).className.split(' ').has(className);}

function getElementsByClass(className, tagName, parentNode) {parentNode = !isUndefined(parentNode)? getElem(parentNode) : document;if (isUndefined(tagName)) tagName = '*';return filter(parentNode.getElementsByTagName(tagName),function(elem) { return hasClass(elem, className) });}

function listen(event, elem, func) {elem = getElem(elem);if (elem.addEventListener)

elem.addEventListener(event,func,false);else if (elem.attachEvent)

elem.attachEvent('on'+event, function(){ func(new W3CDOM_Event(elem)) } );else throw 'cannot add event listener';}

function mlisten(event, elem_list, func) {map(elem_list, function(elem) { listen(event, elem, func) } );}

function W3CDOM_Event(currentTarget) {this.currentTarget  = currentTarget;this.preventDefault = function() { window.event.returnValue = false }

return this;}

function isUndefined(v) {var undef;return v===undef;}

var _POPUP_FEATURES = '';function raw_popup(url, target, features) {if (isUndefined(features)) features = _POPUP_FEATURES;if (isUndefined(target)) target   = '_blank';var theWindow = window.open(url, target, features);theWindow.focus();return theWindow;}

function link_popup(src, features) {return raw_popup(src.getAttribute('href'), src.getAttribute('target') || '_blank', features);}