常用函数封装
1. 获取元素ID var getDom = function(id){ return document.getElementById(id); } 2. 增加事件监听事件 var addEvent = function(id, event, fn){ var el = getDom(id) || document; if(el.addEventListener){ el.addEventListener(event, fn, false); }else if(el.attachEvent){ el.attachEvent('on'+event, fn); } } 3. 获取元素到body边缘的offsetLeft / offsetTop值 var getElementLeft = function(element){ var actualLeft = element.offsetLeft; var current = element.offsetParent; while(current !== null){ actualLeft += current.offsetLeft; current = current.offsetParent; } return actualLeft; } //获取的值是没有'px'单位的 var getElementTop = function