js获取滚动条高度 文档DOM高度 浏览器可视化窗口的高度

//滚动条高度

getScrollTop: function () {

var scrollTop = 0, bodyScrollTop = 0, documentScrollTop = 0;

if (document.body) {

bodyScrollTop = document.body.scrollTop;

}

if (document.documentElement) {

documentScrollTop = document.documentElement.scrollTop;

}

scrollTop = (bodyScrollTop - documentScrollTop > 0) ? bodyScrollTop : documentScrollTop;

return scrollTop;

},

//文档高度

getScrollHeight: function () {

var scrollHeight = 0, bodyScrollHeight = 0, documentScrollHeight = 0;

if (document.body) {

bodyScrollHeight = document.body.scrollHeight;

}

if (document.documentElement) {

documentScrollHeight = document.documentElement.scrollHeight;

}

scrollHeight = (bodyScrollHeight - documentScrollHeight > 0) ? bodyScrollHeight : documentScrollHeight;

return scrollHeight;

},

//浏览器可是高度

getClientHeight: function () {

var windowHeight = 0;

if (patMode == “CSS1Compat”) {

windowHeight = document.documentElement.clientHeight;

} else {

windowHeight = document.body.clientHeight;

}

return windowHeight;

},