经常用到的js函数

//获取样式
function getStyle(obj,attr){
 if(obj.currentStyle){
  return obj.currentStyle[attr]; 
 }else{
  return getComputedStyle(obj)[attr]; 
 }
}

//绑定事件
function addHandler(element,type,handler){
 if(element.addEventListener){
  element.addEventListener(type,handler,false); 
 }else if(element.attachEvent){
  element.attachEvent("on"+type,handler); 
 }else{
  element["on"+type]=handler; 
 }
}

//取消绑定事件
function removeHandler(element,type,handler){
 if(element.removeEventListener){
  element.removeEventListener(type,handler,false);
 }else if(element.detachEvent){
  element.detachEvent("on"+type,handler); 
 }else{
  element["on"+type]=null; 
 }
}

function getById(id){
 id=id+"";
 return document.getElementById(id);
}


function getByClass(obj,className){
 var a=new Array; 
 var b=obj.getElementsByTagName("*");
 for(var i in b){
  if(b[i].className==className){
   a.push(b[i]); 
  }
 }
 return a;
}