js兼容问题总结

var sTop = document.documentElement.scrollTop || document.body.scrollTop

IE:  currentStyle[attr]
标准：getComputedStyle[attr]

function getStyle(obj,attr){
      if(obj.currentStyle){
             return obj.currentStyle[attr]
      }else{
             return getComputedStyle(obj,false)[attr];
      }
  
}

var e = e || event

e.keyCode || e.which

e.preventDefault?e.preventDefault():e.returnValue = false

e.stopPropagation?e.stopPropagation():e.cancelBubble = true

addEventListener()
attachEvent()

removeEventListener()
detachEvent()

e.target || e.srcElement

var xhr = new XMLHttpRequest() || new ActiveXObject(‘Microsoft,XMLHTTP‘)