/*
	DOMAssistant is developed by Robert Nyman, http://www.robertnyman.com, and it is released according to the
	Creative Commons Deed license (http://creativecommons.org/licenses/GPL/2.0/)
	For more information, please see http://www.robertnyman.com/domassistant
*/
var DOMAssistant = {
	methodsToAdd : [],
	baseMethodsToAdd : [
		"elmsByClass",
		"elmsByAttribute",
		"getParentByTagName"
	],
	
	init : function (){
		this.applyMethod.call(window, "$", this.$);
		window.DOMAssistant = this;
		if(window.ActiveXObject && document.all){
			HTMLArray = Array;
		}
		HTMLArray.prototype = new Array;
		HTMLArray.prototype.DOM = this;
		var current;
		for (var i=0; i<this.baseMethodsToAdd.length; i++) {
			current = this.baseMethodsToAdd[i];
			this.methodsToAdd.push([current, this[current]]);
			HTMLArray.prototype[current] = HTMLArrayBaseMethods[current];
		};
	},
	
	applyMethod : function (method, func){
		if(typeof this[method] != "function"){
			this[method] = func;
		}
	},
	
	addMethods : function (elm){
		if(elm){
			var elms = (elm.constructor == Array)? elm : [elm];
			for(var i=0; i<elms.length; i++){	
				for(var j=0; j<this.methodsToAdd.length; j++){
	            	this.applyMethod.call(elms[i], this.methodsToAdd[j][0], this.methodsToAdd[j][1]);
	            }
			}
		}
	},
	
	$ : function (){
		var elm = null;
		if(document.getElementById){
			elm = (arguments.length > 1)? new HTMLArray() : null;
			var current;
			for(var i=0; i<arguments.length; i++){
				current = arguments[i];
				if(typeof current != "object"){
					current = document.getElementById(current);
				}
				if(arguments.length > 1){
					elm.push(current);
				}
				else{
					elm = current;
				}
			}
			DOMAssistant.addMethods(elm);
		}
		return elm;
    },
	
	getParentByTagName : function(tag){
		var elm = this;
		var pattern = new RegExp(tag, "i");
		while(elm.parentNode && !pattern.test(elm.nodeName) && !/body/i.test(elm.nodeName)){
			elm = elm.parentNode;
		}
		return elm;
	},
	
	elmsByClass : function (className, tag){
		var returnElms = new HTMLArray();
		if(document.evaluate){
			var xPathNodes = document.evaluate(".//" + (tag || "*") + "[contains(concat(' ', @class, ' '), ' " + className + " ')]", this, null, 0, null);
			var node = xPathNodes.iterateNext();
			while(node){
				returnElms.push(node);
				node = xPathNodes.iterateNext();
			}
		}
		else{
			var elms = this.getElementsByTagName(tag || "*");			
			var regExp = new RegExp("(^|\\s)" + className + "(\\s|$)");
			for(var i=0,elm,elmsLength = elms.length; i<elmsLength; i++){
				elm = elms[i];		
				if(regExp.test(elm.className)){
					returnElms.push(elm);
				}
			}
		}
		return returnElms;
	},
	
	elmsByAttribute : function (attr, attrVal, tag){
		var returnElms = new HTMLArray();
	    if(document.evaluate){
			var attributeVal = (typeof attrVal == "undefined" || attrVal == "*")? "" : " = '" + attrVal + "'";
			var xPathNodes = document.evaluate(".//" + (tag || "*") + "[@" + attr + attributeVal + "]", this, null, 0, null);
			var node = xPathNodes.iterateNext();
			while(node){
				returnElms.push(node);
				node = xPathNodes.iterateNext();
			}
		}
		else{
			var elms = ((!tag || tag == "*") && this.all)? this.all : this.getElementsByTagName(tag || "*");
			var attributeVal = (typeof attrVal == "undefined" || attrVal == "*")? null : new RegExp("(^|\\s)" + attrVal + "(\\s|$)");
		    for(var i=0,current,currentAttr,elmsLength = elms.length; i<elmsLength; i++){
		        current = elms[i];
		        currentAttr = current.getAttribute(attr);
		        if(typeof currentAttr == "string" && currentAttr.length > 0){
		            if(!attributeVal || typeof attributeVal == "undefined" || (attributeVal && attributeVal.test(currentAttr))){
						returnElms.push(current);
		            }
		        }
		    }
		}
	    return returnElms;
	}	
}

function HTMLArray(){
	// Constructor
}

var HTMLArrayBaseMethods = {	
	elmsByClass : function (className, tag){
		var elmsWithClass = new HTMLArray();
		var elms;
		for (var i=0; i<this.length; i++) {
			elms = this.DOM.elmsByClass.call(this[i], className, tag);
			for (var j=0; j<elms.length; j++) {
				elmsWithClass.push(elms[j]);
			}
		}
		return elmsWithClass;
	},
	elmsByAttribute : function (attr, attrVal, tag){
		var elmsWithAttr = new HTMLArray();
		var elms;
		for (var i=0; i<this.length; i++) {
			elms = this.DOM.elmsByAttribute.call(this[i], attr, attrVal, tag);
			for (var j=0; j<elms.length; j++) {
				elmsWithAttr.push(elms[j]);
			}
		}
		return elmsWithAttr;
	}
};

DOMAssistant.init();