js模仿jquery里的几个方法parent, parentUntil, children

有时工作需要, 也是接着上一章的方法, 用js模仿jquery里的几个方法parent, parentUntil, children.

function parent(node){
    return node.parentNode || null;
}

function parentUntil(node, parentNode){
    while(parent(node) != parentNode){
        node = parent(node);
    }
    return parentNode;
}

function children(parentNode){
    var children,
        length,
        nodeArray = [],
        i = 0;
    if(parentNode.nodeType === 1){
        children = parentNode.children || parentNode.childNodes; //兼顾一下ff3.6以下的版本, 当然也可以不考虑了, 直接用children
        length = children.length;
        for(; i < length; i++){
            if(children[i].nodeType !== 1){
                continue;
            }
            nodeArray.push(children[i]);
        }
        return nodeArray;
    }
    else{
        return null;
    }
}