function getClassNames(classStr,tagName){
if (document.getElementsByClassName) {
return document.getElementsByClassName(classStr)
}else {
var nodes = document.getElementsByTagName(tagName),ret = [];
for(i = 0;
i < nodes.length;
i++) {
if(hasClass(nodes[i],classStr)){
ret.push(nodes[i])
}
}
return ret;
}
}
function hasClass(tagStr,classStr){
var arr=tagStr.className.split(/\s+/ );
//这个正则表达式是因为class可以有多个,判断是否包含
for (var i=0;
i
