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;
    }