HTML DOM操作

1、getElementsByClassName() HTML5新增  

function getElementsByClassName(node, classname){
    if(node.getElementsByClassName){ //注意，这里不加括号
        return node.getElementsByClassName(classname);
    }else{
        var elements = new Array();
        var eles = node.getElementsByTagName("*");
        for(var ele in eles){
            var names = ele.className.split("");
            for(var name in names){
                if(name === classname){
                    elements.push(ele);
                }
                break;
            }
        }        
    }
}

 2、实现insertAfter()

function insertAfter(oldnode, newnode){
    var parent = oldnode.parentNode;
    if(parent.lastChild === oldnode){
        parent.appendChild(newnode);
    }else {
        var sibling = oldnode.nextsibling;
        parent.insertBefore(newnode, oldnoe.nextSibling);
    }
}

3、在window.onload中添加多个函数

function addLoadFunction(func){
    var oldonload = window.onload;
    if(typeof window.onload != 'function'){ //我觉得判断条件也可以为(!oldonload)
        window.onload = func;
    }else {
        window.onload = function() {
            oldonload();
            func();
        }
    }
}