js兼容性

JS的兼容性：
1.ev||event
2.addEventListener||attachEvent
3.document.documentElement.scollTop||body
4.getElementsByClassName
5.setCapture
6.firstChild||element
7.localStorage
8.srcElement||target
9.fromElement||relatedTarget
10.currentStyle||getComputedStyle
11.preventDefault()
12.wheelDetal||detail
13.DOMContentLoaded||onreadystatechange
14.onmousewheel||DOMMouseScroll
15.XMLHttpRequest||ActiveXObject
16.use strict
17.querySelector
18.oninput||onpropertychange
19.pageX=clientX+scrollLeft