function getClass(param){
if(id.getElementsByClassName){
return id.getElementsByClassName(param);
}else{
var allTag = document.getElementsByTagName("*");
var arr = [];
for(var i=0;i<allTag.length;i++){
var className = allTag[i].className;
var arrClass = className.split(" "); //多個類名的處理 分割開
for(var j=0;j<arrClass.length;j++){
if(arrClass[j]==param){
arr.push(allTag[i]);
}
}
};
return arr;
};
};