js常用方法（。。。。不完整）

lastIndexOf();
substring();
split();
slice();
splice();

var s="http://www.baidu.com";
var i= s.lastIndexOf("."); //16
var unit= s.substring(i); //.com
var url= s.substring(0,i);  //http://www.baidu

addLoadEvent(func1);
addLoadEvent(func2);
function addLoadEvent(func){
var oldonload=window.onload;
if(typeof window.onload!='function'){
window.onload=func;
}else{
window.onload=function() {
oldonload();
func();
}
}
};
function func1(){
alert("text1");
};
function func2(){
alert("text2");
};

<ul id="imagegallery">
<li><a href="images/ads/1.jpg" title="广告1">广告1</a></li>
<li><a href="images/ads/2.jpg" title="广告2">广告2</a></li>
<li><a href="images/ads/3.jpg" title="广告3">广告3</a></li>
<li><a href="images/ads/4.jpg" title="广告4">广告4</a></li>
</ul>
<p id="description">Choose an image</p>
<img id="placeholder" src="images/ads/adindex.gif" alt="my image gallery">

window.onload = prepareGallery();
function prepareGallery() {
if (!document.getElementsByTagName) return false;
if (!document.getElementById) return false;
if (!document.getElementById("imagegallery")) return false;
var gallery = document.getElementById("imagegallery");
var links = gallery.getElementsByTagName("a");
for (var i = 0; i < links.length; i++) {
links[i].onclick = function () {
return showPic(this) ? false : true;
}
}
}
function showPic(whichpic) {
if (!document.getElementById("placeholder")) return false;
var sourse = whichpic.getAttribute("href");
var placeholder = document.getElementById("placeholder");
if (placeholder.nodeName != "IMG") return false;
placeholder.setAttribute("src", sourse);
//
if (document.getElementById("description")) {
var text = whichpic.getAttribute("title") ? whichpic.getAttribute("title") : "";
var description = document.getElementById("description");
if (description.firstChild.nodeType == 3) {
description.firstChild.nodeValue = text;
}
}
return true;
}