JavaScript 通过 class 获取元素的方法

 
function getByClass(classname) {
var nodes = document.getElementsByTagName('*'),
ret = [];
for (var i = 0; i < nodes.length; i++) {
if (hasClass(nodes[i], classname))
ret.push(nodes[i]);
} 
return ret;
} 
function hasClass(node, className) {
var names = node.className.split(/\s+/);
for (var i = 0; i < names.length; i++) {
if (names[i] == className)
return true;
} return false;
}