function xAppendChild(oParent, oChild){
	if(oParent.appendChild){
		return oParent.appendChild(oChild);
	}else{
		return null;
	}
}

function xCreateElement(sTag){
	if(document.createElement){
		return document.createElement(sTag);
	}else{
		return null;
	}
}

function xFirstChild(e, t){
	var c = e ? e.firstChild : null;
	if(t){
		while(c && c.nodeName != t){
			c = c.nextSibling;
		}
	}else{
		while(c && c.nodeType != 1){
			c = c.nextSibling;
		}
		return c;
	}
}

function xGetComputedStyle(oEle, sProp, bInt){
	var s, p = 'undefined';
	var dv = document.defaultView;
	if(dv && dv.getComputedStyle){
		s = dv.getComputedStyle(oEle,'');
		if(s){
			p = s.getPropertyValue(sProp);
		}
	}else if(oEle.currentStyle){
		var a = sProp.split('-');
		sProp = a[0];
		for(var i=1; i<a.length; ++i){
			c = a[i].charAt(0);
			sProp += a[i].replace(c, c.toUpperCase());
		}
		p = oEle.currentStyle[sProp];
	}else{
		return null;
	}
	return bInt ? (parseInt(p) || 0) : p;
}

function xGetElementsByAttribute(sTag, sAtt, sRE, fn){
	var a, list, found = new Array(), re = new RegExp(sRE, 'i');
	list = xGetElementsByTagName(sTag);
	for(var i = 0; i < list.length; ++i){
		a = list[i].getAttribute(sAtt);
		if(!a){
			a = list[i][sAtt];
		}
		if(typeof(a)=='string' && a.search(re) != -1){
			found[found.length] = list[i];
			if(fn){
				fn(list[i]);
			}
		}
	}
	return found;
}

function xGetElementsByClassName(c,p,t,f){
	var found = new Array();
	var re = new RegExp('\\b'+c+'\\b', 'i');
	var list = xGetElementsByTagName(t, p);
	for(var i = 0; i < list.length; ++i){
		if(list[i].className && list[i].className.search(re) != -1){
			found[found.length] = list[i];
			if(f){
				f(list[i]);
			}
		}
	}
	return found;
}

function xGetElementsByTagName(t,p){
	var list = null;
	t = t || '*';
	p = p || document;
	if(xIE4 || xIE5){
		if(t == '*'){
			list = p.all;
		}else{
			list = p.all.tags(t);
		}
	}else if(p.getElementsByTagName){
		list = p.getElementsByTagName(t);
		return list || new Array();
	}
}

function xInnerHtml(e,h){
	if(!(e=xGetElementById(e)) || !xStr(e.innerHTML)){
		return null;
	}
	var s = e.innerHTML;
	if(xStr(h)){
		e.innerHTML = h;
	}
	return s;
}

function xNextSib(e,t){
	var s = e ? e.nextSibling : null;
	if(t){
		while(s && s.nodeName != t){
			s = s.nextSibling;
		}
	}else{
		while(s && s.nodeType != 1){
			s = s.nextSibling;
		}
		return s;
	}
}

function xPrevSib(e,t){
	var s = e ? e.previousSibling : null;
	if(t){
		while(s && s.nodeName != t){
			s=s.previousSibling;
		}
	}else{
		while(s && s.nodeType != 1){
			s=s.previousSibling;
		}
		return s;
	}
}

function xWalkEleTree(n,f,d,l,b){
	if(typeof l == 'undefined'){
		l = 0;
	}
	if(typeof b == 'undefined'){
		b = 0;
		var v = f(n,l,b,d);
	}
	if(!v){
		return 0;
	}
	if(v == 1){
		for(var c = n.firstChild; c; c = c.nextSibling){
			if(c.nodeType == 1){
				if(!l){
					++b;
				}
				if(!xWalkEleTree(c,f,d,l+1,b)){
					return 0;
				}
			}
		}
	}
	return 1;
}

function xWalkTree(n, f){
	f(n);
	for(var c = n.firstChild;c; c = c.nextSibling){
		if(c.nodeType == 1){
			xWalkTree(c, f);
		}
	}
}