jjavascript 高度相关

//scrollTop;
var scrollTop = Math.max(document.documentElement.scrollTop, document.body.scrollTop);

// 屏幕可视区高度
var viewHeight = document.compatMod === ‘CSS1Compat‘ ? document.documentElement.clientHeight : document.body.clientHeight;

// 文档高度

var documentHeight = document.compatMod === ‘CSS1Compat‘ ? document.documentElement.scrollHeight: document.body.scrollHeight;